OpenGL example: allow resizing window.

Fix Clang warning with offsetof() macro? Added -Wall in OpenGL 3 example.

Examples: DirectX11: moved shader to be close to its usage location,

Examples: OpenGL3: cleaned up to match features of OpenGL2 example

Examples: adding title to the top of each examples. Cleaning up file headers.

Example apps: accumulate mouse wheel to accodomate for slow framerate.

DirectX11 example: further tweaks/massaging (-15 lines). Syncing example.

Removed Microsoft IME handler in examples, too confusing. Moved to imgui.cpp instruction block.

Tab->Spaces :(

Added DirectX11 example application (code is too long!)

Example code: warning fix + comments.

Updated example code.

Moved IO.Font*** options to inside the IO.Font-> structure.. Added IO.FontGlobalScale setting (vs Font->Scale)

Renamed ImBitmapFont -> ImFont, removed abstraction-pretend typedef

Fixed compatibility with std::vector if user decide to #define ImVector

OpenGL example: uses offsetof() macros for vertice definition instead of hardcoded offsets

OpenGL example: made the render function save/restore OpenGL state properly-ish

OpenGL/DirextX examples: comments and tweaks.

OpenGL example: Tentative fix for missed tap-to-click events on MacBook trackpad

OpenGL example: minor tweak for non-default font.

OpenGL/DirectX examples: support for international text input in UTF-8 + implement ImeSetInputScreenPosFn on Windows.

OpenGL example: added commented code to load custom font from filesystem

OpenGL example: comments on glfw window size vs frame buffer size.

Add support for Retina displays on MacOSX.

Fixes to allow clean 1-pixel thick lines in more use cases. PixelCenterOffset not the same as previously!

Minor text alignment

Added comments

Disable client state in OpenGL example after rendering. ...

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.

Converted all Tabs to Spaces (git diff -w shows an empty diff)

Tidying up example applications so it looks easier to just grab code