Use more robust CodeMirror version checking
Use more robust CodeMirror version checking

Fixes #167

murugespandian/firepad,STRd6/firepad,shadowcodex/firepad-rethinkdb,missive/firepad,JudeMartin/firepad,Unrestricted-Coding/firepad-rethinkdb,abhishekgahlot/firepad,woutie012006/firepad,STRd6/firepad,kofifus/firepad,JudeMartin/firepad,woutie012006/firepad,nagyistoce/firebase-firepad,JudeMartin/firepad,kofifus/firepad,nagyistoce/firebase-firepad,STRd6/firepad,gching/firepad,Unrestricted-Coding/firepad-rethinkdb,dipankar08/firepad,missive/firepad,shadowcodex/firepad-rethinkdb,murugespandian/firepad,abhishekgahlot/firepad,dipankar08/firepad,gching/firepad,dipankar08/firepad