Cleanup superfluous includes in main.h.
Cleanup superfluous includes in main.h.

Used cppclean for code analysis:  https://code.google.com/archive/p/
cppclean/

GregoryBetz/DarkSilk-Release-Candidate,GregoryBetz/DarkSilk,GregoryBetz/DarkSilk-Release-Candidate,GregoryBetz/DarkSilk,GregoryBetz/DarkSilk-Release-Candidate,GregoryBetz/DarkSilk,GregoryBetz/DarkSilk,GregoryBetz/DarkSilk-Release-Candidate,GregoryBetz/DarkSilk-Release-Candidate,GregoryBetz/DarkSilk,GregoryBetz/DarkSilk-Release-Candidate,GregoryBetz/DarkSilk