mergetools: improve configuration for several merge tools
* meld - provide labels for the three panes
* diffmerge - add registry key for detection, improve arguments
* beyond compare - add linux version
* winmerge - improve arguments
* araxis - add configuration, including registry key for detection
* misc - provide default priorities for more tools
adding dir/bar
adding foo
dir/bar
foo
committed changeset 0:d44511117907
adding dir/bar_2
adding foo_2
dir/bar_2
foo_2
committed changeset 1:a85812e0561a
adding a
adding c
removing a
adding b
removing c
adding d
recording removal of a as rename to b (100% similar)
removing a
adding b
removing c
adding d
recording removal of a as rename to b (100% similar)