Add functions to system.perspective to replace (update) style groups, add style groups, or delete style groups.

Something like 'system.perspective.alterCSS()' with parameters to pass in the formatted CSS group as a string and the type of alteration to be done (replace, append, delete).

Also, add something like 'system.perspective.getCSS()' so the current stylesheet could be retrieved and saved as a new style (via scripting to save a new .css file in the install directory).

This would allow custom styles to be created/edited on the fly, and easily save/delete them.