Added clearGroup and removeObject functions (API and viewer).
Renamed figure and clear to newFigure and clearFigure in API for clarity
Renamed connect and disconnect to beginDrawing and endDrawing in API.
Doxygen documentation of C++ API
Added closeFigure in C++ API.
Merge pull request #56 from dvinc/master

Doxygen. clearGroup,removeObject,closeFigure. Renaming of figure,clear,connect,disconnect in API