Merge pull request #99 from mantidproject/bugfix/10740_mdviewer_crash_linux

All seems fine, it was tested on Ubuntu and Windows 7
Use unix-style line endings on OSX.

This is what later versions of QScintilla as CR is a pre-OSX thing.
Refs #10654
Merge branch 'bugfix/10654_osx_script_editor_eol' into develop