Add option to disable obsolute ImGui functions #487

Job	Run time
clang-format	8s
Windows MSVC Shared Release	1m 3s
Windows MSVC Shared Debug	1m 20s
Windows MSVC Static Release	1m 3s
Windows MSVC Static Debug	1m 1s
Windows ClangCL Shared Release	1m 21s
Windows ClangCL Shared Debug	1m 45s
Windows ClangCL Static Release	2m 3s
Windows ClangCL Static Debug	2m 4s
Windows Clang Shared Release	1m 48s
Windows Clang Shared Debug	1m 35s
Windows Clang Static Release	2m 1s
Windows Clang Static Debug	2m 0s
Linux GCC Shared Release	53s
Linux GCC Shared Debug	35s
Linux GCC Static Release	1m 5s
Linux GCC Static Debug	52s
Linux Clang Shared Release	50s
Linux Clang Shared Debug	36s
Linux Clang Static Release	1m 14s
Linux Clang Static Debug	1m 1s
macOS Clang Shared Release	1m 59s
macOS Clang Shared Debug	1m 58s
macOS Clang Static Release	1m 31s
macOS Clang Static Debug	53s
	32m 39s

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