Added friendly message about removing a group that still contains subgroups. Fixed option to remove a group that is not in filesystem (ex. someone deleted it intentionally on filesystem) in this case RhodeCode will simply just throw an error message saying this group cannot be deleted.

syntax: glob
*.pyc
*.swp

syntax: regexp
^build
^docs/build/
^docs/_build/
^data$
^\.settings$
^\.project$
^\.pydevproject$
^rhodecode\.db$
^test\.db$
^repositories\.config$
^RhodeCode\.egg-info$