Add CSS Class property merge syntax support

Hey Zach - Here’s a few that I’ve come across:

1) Styling Field Editors based on row props/values is one of them.  However, rather than put a cssclass on each individual field editor on a page, I’d like to conditionally apply a class to the page itself in a master page (single point of maintenance).  Currently, there is no CSS Class property on the page itself (possibly there should be??) so I was going to put everything inside of a wrapper and do conditional CSS on the wrapper.

2) User Preferences - Being able to conditionally apply a class to a wrapper would allow an easy way to customize minor differences in styling across the page based on user preferences.  For example, yesterday some users wanted the “help” icons removed (less distracting).  I can apply a sk-icon-help { display: none; } rule and then conditionally apply the class to the page/wrapper/etc.

3) Tables, Templates, RTF, etc. could also conditionally be styled based on row properties.  Similar need to #1.

I think the main reason for having “all” components apply merge syntax on CSS Class is for consistency (better than some do and some don’t I think).  This is, of course, unless there is another reason not to (e.g. perf hit, etc.).  

Thanks!