Adding image directory..
Merging with upstream:master and cleaning up.
Fixes: SVGs are exported to dm4.filerepo or user.home.
Features: Grouping topics and assocs in SVG file export
Switched to dialog after successfull export.
Revised string concatenation for dialog-message.
Fixes: Group the whole SVG-graph #5
Merge pull request #6 from mukil/master

Fixes: Topicmap SVG export is filed in dm4.filerepo or user directory