* Add some ifdefs to add emscripten specific params and includes
* Update imgui_impl_opengl3.cpp
* Update imgui_impl_opengl3.cpp
* Update imgui_impl_opengl3.cpp
* replace __EMSCRIPTEN_BUILD__ with __EMSCRIPTEN__
* replace GLFW_INCLUDE_ES3 with direct header
* removing useless glfw include
* Making call to glPolygonMode() optional
Read examples/README.txt for some details.
ImDrawData: Added DisplayPos, DisplaySize fields honored by all backends (not strictly necessary to honor just now, but doing it to be ahead)