Add vertical text support in Mac port

Draw text vertically if the flag in the scaler is set.

The general strategy is to get the vertical advance, and correct the glyph's left and top by the font's vertical offsets.

Add specialization to work around a Snow Leopard in CTFontGetVerticalTranslationsForGlyphs. 

The font size can be retrieved more reliably from the scaler than from the CTFont -- use fTextSize instead of CTFontGetSize.

Use the CTFontGetUnitsPerEm instead of reading the font data directly.

Add a utility to flip the matrix to account for different Y axis directions.

Set the newly created CTFont to have a vertical attribute dictionary entry as appropriate

[reed1, 2011-11-10 18:17:20]

nit about inttoscalar(90)

lgtm

http://codereview.appspot.com/5375053/diff/1/src/ports/SkFontHost_mac_coretex...
File src/ports/SkFontHost_mac_coretext.cpp (right):

http://codereview.appspot.com/5375053/diff/1/src/ports/SkFontHost_mac_coretex...
src/ports/SkFontHost_mac_coretext.cpp:669: } else {
SkIntToScalar(90)