Add the ability to open files to a selected line/column.

Add the ability to open files with paths of the form "path[:lineNumber[:columnNumber]]". 

This change adds a new apple event that can be sent to brackets by other apps on macintosh. Coming soon will be additional changes to provide this functionality on the mac and windows command-line. I have also submitted a pull request for a corresponding change to the brackets project.

This change also includes a fix for a crash that occurs when Brackets is running and you do 'open <file> -a "Brackets"' from the command line.