Javascript Region Folding

See [Discussion] (https://groups.google.com/forum/#!topic/ace-discuss/JkeDqTJAUso)

*Harutyun Amirjanyan: but since vs and webstorm support i am not opposed to including it (either default or as an extension) if required changes are small
create the pull request and i'll have a look.*
Indeed this is not very nice, perhaps not using getFoldWidget of base class will make code simpler and will allow to do fewer regexp test calls.
I'll try to think of a better solution before merging this pull request.