Improve sorting in the track tables BPM Options submenu

Sort by the most used options and add some separators for clarity.
Also rename the submenu from BPM Settings > BPM Options. IMO this is
the more correct term since the menu contains the available options for
the BPM setting of a track.
Merge commit '87ea884419af41071c6a334a32a3d3b4e6222f38'
Merge branch 'mixxxdj/mixxx/tree/master' into 'esbrandt/mixxx/tree/master'

Conflicts:
	mixxx/src/widget/wtracktableview.cpp
Fix merge conflict from last commit
This adds the missing 2/3 and 4/4 BPM options to the BPM tab in the trackeditor window. It also adds some tooltips and fixes the tab order. Could use some wordsmithing on the tooltips though. Thanks.
Arrange BPM buttons in track editor in 1 2x2 grid
Merge pull request #12 from esbrandt/master

Improve sorting in the track tables BPM Options submenu