Accept folders dropped on the icon
Switch to file.openDroppedFiles command so that users can drop a folder as a new project.
Handle multiple files drop on top on Brackets shortcut on Windows.
Correct a logic error even though "nextQuoteIndex > 0" works when there is no quote since npos is a large positive number.
Merge pull request #361 from adobe/rlim/handle-dropped-folder

Allow folder drop on top of Brackets app.
Merge pull request #353 from eugeneo/folderdrag

[Mac] Accept folder dropped on shell icon