Make struct ImFontConfig match imgui's.

Fixes problems using custom fonts.

update readme

revert missing ImFontConfig_DefaultConstructor, fix fn name ImFont_Ge…

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Update README.md

Update to imgui 1.51 (cimgui#34)

* Updated imgui submodule to v1.51 tag

* Updated API to imgui 1.51

* Fix all compiler and linker errors

Add ImGuilistClipper struct under CIMGUI_DEFINE_ENUMS_AND_STRUCTS

add missing new param

was introduced in 1.50