Clean up install handling
Remove Darwin physfs hacks

When physfs is in the library search path, the regular usage of adding
physfs to LIBS is sufficient.
Remove duplicate FRAMEWORKS setup
Move */arch/cocoa -> common/arch/cocoa
Move */arch/carbon -> common/arch/carbon
Move char_bm into gr_internal_color_string
Switch gr_printf(x,y,s) to gr_string(x,y,s)
Mark various newmenu strings as const