Fixed ImGuiTextFilter triming of leading/trailing blanks. Documented "Filtering" section of demo better.

Disable client state in OpenGL example after rendering.

Fixed file descriptor leak on LoadSettings() failure

Using the example code in another application that has other rendering
code can cause rendering bugs or memory access errors if client state
is not disabled.

Argh

from arikwestbrook

Note that this is never a good idea. But, allowing it reduce confusion
in the initial stage of setup.

Fixed floating-point precision issue making the right-side value of a plot sometimes wrap to the left-side value.

TreeNode/CollapsingHeader ignore clicks when CTRL or SHFIT are held + make default button hover brighter