preview_mode dev preview
added config setting for preview_mode (default false)
finalized preview_mode with save or edit removing preview status
preview_mode cleanup
preview_mode: added spec, made settings and new file no longer trigger closePreview() and fixed some code review changes
preview_mode: removed debug behaviour
preview_mode fix undefined check
Merge branch 'preview_mode' of https://github.com/dcunited08/atom