Base Graphics Conversion TODO list

• Move remaining RGraphics.h API to GraphicsEngine.h/GraphicsDevice.h API. Examples: Rf_str2col, Rf_addDevice.
• Currently there is a lot of duplication with G* graphical primitives in graphics.c and GE* counterparts in engine.c. The G* functions can be gutted and turned into wrappers which call the GE* functions to minimise disruption of users of RGraphics.h until the big switch (at 2.0?). Examples of this are in plotmath.c (e.g., old GMathText wrapper for GEMathText). NOTE: care must be taken when doing this to check for possible incompatibilities between the G* code and the GE* code (e.g., if a bug fix has been applied to the G* code only, we don't want to lose it(!)
  Done in development version (post 1.8.0).
• Add version support so that external code can check which version of the graphics API they are dealing with.
  Thanks to Thomas Baier for useful discussion on this so far.