Disable quote substitution in FScriptTextView.m

Fixes "F-Script syntax error: non ascii character detected" in OS X Mavericks when trying to create a string. See https://groups.google.com/forum/#!topic/f-script/FJVIhPtHGj4
Merge pull request #9 from ludwig/patch-1

Disable quote substitution in FScriptTextView.m