Resolve color xml attributes properly.

Color attributes were not being converted to int properly. The
conversion to int was a simple string to int using base 16. This change
resolves the colors as per #RGB, #ARGB, #RRGGBB or #AARRGGBB format
depending on the length of the attribute. All values that begin with '#'
are treated as colors.

Bug: http://b.android.com/73845
Change-Id: I8ad089b821af1e290b9b95771b50213fe2fdd784