Initial commit
Add bookmark folders as context menu
Localize user string in the javascript code
Make "command" method only applies to menuitem

This commit fix the bug that covering the "scroll button" triggers
the "command" event.
Make sure our destination is a bookmark folder
Try the parent document if no stringBundle found

Bookmarks side panel has no stringbundleset defined, so the parent
docment has to be quried.
Add screenshots for version 0.1
Merge branch 'release/0.1' into develop
Use combination inheritance instead
Better way to determine root node
Use parent node's _placesNode attribute
Change to a better variables naming
Separate Places nodes moving method
Change label to "Move To This Folder"
Able to move into a newly created sub folder
Prevent "Open All In Tabs" menuitem from being shown
Move 'stringBundle' getter into 'placesUIOverlay'
Add screenshots for version 0.2
Bump version number to 0.2
Merge branch 'release/0.2' into develop