Initial implementation of SON to CSS generator

Signed-off-by: Rik Cabanier <cabanier@adobe.com>
code cleanup of SON to CSS generator
change SONToCSS.convert to use document ID from document manager
enable/disable CSS menu based on current selection
Add mising .done() to main getStyleInfo call
Merge pull request #258 from adobe-photoshop/rc/css-api

Initial implementation of experimental SON to CSS generator