Prepare fixes for v0.7.1 instead of v0.8.0
Properly escape executable and temp files. Support spaces in names.
Should also fix clue/graph-uml#30
Start a temporary background shell when opening images on MS Windows.
We do not want to block and this is the equivalent of a fork().
Add improved GraphViz to CHANGELOG
Merge branch 'fix-graphviz-windows' into 0.7.x
Prepare v0.7.1 release
Merge branch '0.7.x'

Conflicts:
	CHANGELOG.md