[PSDK][GDIPLUS]
Make previously untested GDI+ C++ wrappers compilable. This involves:
- adding the respective headers to gdiplus.h in a sensible order
- adding forward-declarations
- adding friend-declarations, so that the wrapper functions in those classes can access the private GpXXX members
- const-qualifying the getters in class Color
- adding the EmfToWmfBitsFlags enum
- commenting out bits that use unavailable flatapi functions
- commenting out bits that for some reason the compiler does not like
- the typical typo/data type fixes that untested code tends to need
- moving the Font class within the same header to fulfill dependencies
- adding private GpXXX members to otherwise unimplemented classes
- adding a data-members-only implementation of SizeF
svn path=/trunk/; revision=72852