Update README.md

Fixed typos, reworded sentence.
Added more comments in the code.
Made radio button render ascii when logged into tty/file/clipboard
Added ImGuiInputTextFlags_EnterReturnsTrue
Merge pull request #44 from xythobuz/master

Added ImGuiInputTextFlags_EnterReturnsTrue
Added extra_flags parameters to InputInt(), InputFloat(). Used in example code. Commented out broken ImGuiInputTextFlags_AlignCenter.
Added #define IMGUI_INCLUDE_IMGUI_USER_CPP to optionally include imgui_user.cpp
Update README.md
Fixed file-descriptor leak if ImBitmapFont::LoadFromFile() calls to seek/tell fails.
Added version number in sources
Update README.md
Merge remote-tracking branch 'upstream/master'