Add missing parent svg element and id attribute to SVG font

I made the change only in the regular version so far.
The change shall be generalized.

The svg element is needed to identify the file as an SVG document
and the font as an SVG font element, and the id to reference the
font element from a font-face declaration.
Add missing id attribute on SVG font elements
Add missing root svg element around SVG fonts
Add missing id to reference SVG font from CSS font-face declaration
Complete font-face declarations for all weights of Source Code Pro
Add missing id to reference SVG font from CSS font-face declaration
Complete CSS declarations for all weights/styles of Source Sans Pro
Merge branch 'typeface' into enhancements
Disable hidden options to make sure that they cannot be selected

IE and Safari do not support hiding options so far. With this change,
the options are at least grayed out and cannot be selected.
Merge branch 'enhancements'