Scrolling, Nav: Fixed programmatic scroll leading to a slightly incorrect scroll offset when the window has decorations or a menu-bar (broken in 1.71). This was mostly noticeable when a keyboard/gamepad movement led to scrolling the view, or using e.g. SetScrollHereY() function. Fix/amend a0994d74.

Internal: Moved NavScrollToBringItemIntoView() declaration to imgui_internal.h. Fixed spacing missing in 494d8047. Fixed changelog wreck from 1.72.

Nav: Fixed an issue with NavFlattened window flag where widgets not entirely fitting in child window (often selectable because of their extruded bits) would be not considered to navigate toward the child window. (#787)
This creates a little bit of tension because g.NavDisableHighlight tends to makes the reference point not always visible.
Amend c665c15a

Demo: Showing how to use the format parameter of Slider/Drag functions to display the name of an enum value instead of the underlying integer value

Fixed Clang 8.0 warning "empty expression statement has no effect; remove unnecessary ';' to silence this"  warning [-Wextra-semi-stmt]
+ Comment

Internals: Added IMGUI_DEBUG_INI_SETTINGS. Made IMGUI_DEBUG_LOG redefinable in imconfig.h. Comments. Fix to allow Metrics's NodeWindow() being called with a NULL window.

Demo: Using ImGuiColorEditrFlags instead of int.

This fixes gcc warning: missing field 'alloc' initializer [-Wmissing-field-initializers]

Scrolling: Made mouse-wheel scrolling lock the underlying window until the mouse is moved again or until a short delay expires (2 seconds). This allow uninterrupted scroll even if child windows are passing under the mouse cursor. (#2604)

Scrolling: Made it possible for mouse wheel and navigation-triggered scrolling to override a call to SetScrollX()/SetScrollY(), making it possible to use a simpler stateless pattern for auto-scrolling.
Demo: Log, Console: Using a simpler stateless pattern for auto-scrolling.

Fixed Travis-CI banner address.

Increased IMGUI_VERSION_NUM to facilitate transition of OSX clipboard support for framework using/embedding any version of imgui. Amend 29d9394a. (#2546)

Backends: DX10/DX11: Backup, clear and restore Geometry Shader is any is bound when calling renderer.
Backends: DX11: Clear Hull Shader, Domain Shader, Compute Shader before rendering. Not backing/restoring them.

OSX: Disabled default native Mac clipboard copy/paste implementation in core library (added in 1.71), because it needs application to be linked with '-framework ApplicationServices'. It can be explicitly enabled back by using '#define IMGUI_ENABLE_OSX_DEFAULT_CLIPBOARD_FUNCTIONS' in imconfig.h. Re-added equivalent using NSPasteboard api in the imgui_impl_osx.mm experimental back-end. (#2546)

Adding an ImGuiKey 'ImGuiKey_EnterSecondary' to support platforms that differentiate the enter (return key) and the numpad enter key.

Fixed incorrect application of io.DisplaySafeAreaPadding which would be problematic with multi-viewports when a monitor uses negative coordinates (correct clamping is done right below). (#2674)

Columns: Made GetColumnOffset() and GetColumnWidth() behave when there's no column set, consistently with other column functions + fixed Columns demo (#2683)

Columns: Improved honoring alignment with various values of ItemSpacing.x and WindowPadding.x. (#125, #2666)

Columns: Made the right-most edge reaches up to the clipping rectangle (removing WindowPadding.x*0.5 worth of asymmetrical/extraneous padding). (#125, #2666)
+ Moved a few things in BeginColumns().

Columns: Fix support for BeginColumns() with a count of 1 (not that this isn't available via the old Columns() api). Tweaked Demo to facilitate testing for it.

Debug Tools: Added DebugStartItemPicker() in imgui_internal.h to facilitate binding this anywhere in user's tool. Adedd highlight. Added IMGUI_DEBUG_TOOL_ITEM_PICKER_EX to break in ItemAdd().

Revert "Columns: Improved honoring left-most and right-most alignment with various values of ItemSpacing.x and WindowPadding.x. In particular, the right-most edge now reaches up to the clipping rectangle while ensuring that the right-most column clipping width matches others. (#125, #2666)"

This reverts commit 6c16ba64.

Columns: Improved honoring left-most and right-most alignment with various values of ItemSpacing.x and WindowPadding.x. In particular, the right-most edge now reaches up to the clipping rectangle while ensuring that the right-most column clipping width matches others. (#125, #2666)

Columns: Fixed a regression from 1.71 where the right-side of the contents rectangle within each column would wrongly use a WindowPadding.x instead of ItemSpacing.x like it always did. (#125, #2666)

Misc: Made Button(), ColorButton() not trigger an "edited" event leading to IsItemDeactivatedAfterEdit() returning true. This also effectively make ColorEdit4() not incorrect trigger IsItemDeactivatedAfterEdit() when clicking the color button to open the picker popup. (#1875)
Demo: Added Button with repeater and InputFloat with +/- button to the status query test demo.

Also moved NextColumn between BeginColumn and NextColumn which makes it easier to work on that code.

Fixed old SetWindowFontScale() api value from not being inherited by child window. Added comments about the right way to scale your UI (load a font at the right side, rebuild atlas, scale style).
+ Added missing IMGUI_API marker to the EmptyString storage used by ImGuiTextBuffer. (#2672)

Debug, Metrics: Added "Tools->Item Picker" tool which allow clicking on a widget to break in the debugger within the item code. The tool calls IM_DEBUG_BREAK() which can be redefined in imconfig.h if needed.

Style: Added style.ColorButtonButton (left/right, defaults to ImGuiDir_Right) to move the color button of ColorEdit3/ColorEdit4 functions to either side of the inputs.