GDISP:
Fix gdisp???Arc to use (possibly) hardware accelerated routines.
Fix Arc orientation so 0 degrees is on x axis and 90 degrees points to
the top of screen (instead of the bottom).
Add rounded box routines (if ARC support is turned on).
Add a gdispDrawStringBox to match the gdispFillStringBox routine.
Repair prototypes in wrong place in gdisp.h
GWIN:
Extract the concept of a Window Handle to allow many new features.
Allow dynamic creation of window objects as well as static
initialisation.
Seperate the console code into a console specific window type.
Add buttons as a specific window type. The drawing code is complete, the
input (touch or mouse) is still to be implemented.
Implement gdispFillArc in gdisp.
Added gwin (GFX_USE_GWIN) - adds a window based drawing layer to GDISP.
GWIN also support chprintf text drawing like console.
