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
abort: repository a not found!
255
abort: error: Connection refused
255
abort: repository a not found!
255
abort: Permission denied: ../a
255
abort: repository a not found!
255
destination directory: q
abort: destination 'q' is not empty
abort: destination 'a' is not empty
255
adding c
255
dir is still here
repo is gone