check for mbstring
added preview contextmenu
allow also folders
add single click for filemanager
Merge pull request #495 from daeks/475

Enhancement: add single click for filemanager
Merge pull request #494 from daeks/488

Enhancement: added preview contextmenu
Merge pull request #493 from daeks/491

Fix: check for mbstring
first commit
added manual repo
install manually
first search
update from github