Canvas 2D API chanages

Changes for focus ring and text baseline. The diff.text file highlights the
differences between this new canvas2dapi spec and the existing one. I will
refer to this in the change proposal to break drawfocusring into two
methods for standard and custom focus rings and the added baseline for text
metrics

(See attached file: canvasissue131.html)(See attached file: diff.txt)

Rich Schwerdtfeger
CTO Accessibility Software Group