Sort bookmarks reverse chronologically

This commit fixes bookmark sorting, which before was in respect to the
bookmark title which made no sense what-so-ever. This fix will not sort
the array every time a bookmark is added, but instead just figure out
the newly added bookmarks relative position, and then add it.

Note, that bookmarks that are already placed in books will *not* get
sorted due to the algorithm above.
Merge remote-tracking branch 'tbx/master'
Only set firstPlay when actually playing
Put setting of firstPlay into progress handler
Simplify, simplify, simplify
Merge pull request #618 from saebekassebil/firstplay

Pull in firstPlay fix from stable (2.1.x)
Remember to call play with parenthesis
Forward-slashes in Windows builds
Merge pull request #624 from saebekassebil/wincake

Forward-slashes in Windows builds
Merge branch '2.1.x' into merger
Merge pull request #629 from saebekassebil/merger

Merge stable (2.1.x) into master
Merge pull request #607 from saebekassebil/bookmark-order

Bookmark order
Merge branch 'master' into remove-unused-images