added a high resolution icon
Biggy updates

* Project Tab Manager now treats **all** windows as projects.
    * No need to manually create project
    * Click on "edit" button beside project name to rename
    * Bookmark will be created when you bookmark one of tabs
* Tab order is now synching better than before
* Retina display support
* New icons
Remove non-bound session when all tabs are removed

This leaves non-bound session if the window is closed while some tabs
remain
Experimental Promise use
Reverting Promise for `getWindowInfo`

Didn’t find it useful for this use case.
Session recovery optimisation

Now can recover from crash, profile resume, etc.
Fix for broken summary display
Fix for summary
Added Bookmark annotation
Upgraded Bootstrap
Fixed session tracking bug

This prevented new opened window from creating session
Added `getFavicon` feature

`getFavicon` caches favicon and reduces network access.
Better favicon handling
Added url annotation in <bookmark> tag
Better active window tracking
Use 'Noto Sans' font by default
Fixed locale files
Generate help.html from markdown
Remove contextMenu as it's not used any more
Opaque when tab is not open