Add deprecation warning for global CodeMirror the first time it's called from a given location
Don't get stack if oncePerCaller isn't set
Merge from master
add pref for soft tab
changes for code review
Merge pull request #7205 from adobe/randy/soft-tabs-pref

Add preference for soft tabs
Merge pull request #7190 from adobe/nj/deprecate-global-cm

Add deprecation warning for global CodeMirror the first time it's called from a given location
Update CodeMirror to v4 RC2