when no hostmanager version is given, the frontend now shows "devel" (like in backend/frontend version info in the footer)
added icons to filter dropdowns in host list
added filter icon to resource lists
added another icon
Merge branch 'master' of ssh://github.com/GLab/ToMaTo into restructure_fexes
Merge pull request #437 from t-gerhard/restructure_fexes

Restructure fexes