Unify and adjust spaces and linefeeds.
No more update prefs on the first run.
Adjust code indent
Remove obsolete codes.
Centralize APIs to common.js.
Centralize string APIs.
Move preferences to "extensions.scrapbook.addon.maf.*"
Fix: wrong datetime when converting a folder.
Fix: sub-folders cannot be added to the .maff correctly.
Fix: Supress error messages by no-folder items (eg. separators) when making maffs from a folder.
Fix: Check existence for the output file and do not check existence for recursive files when merging multiple items into one.
Update version info.
Merge branch 'devel'