fix typo in readme
Merge pull request #65 from dominikh/patch-1

fix typo in readme
Updated graphViz to work on OS X

on Mac OS X the way to open a file with the default handler is "open"

I added a switch to reflect this
Fixed code style
Merge pull request #67 from onigoetz/patch-1

Updated graphViz to work on OS X
Add PR#67 to CHANGELOG
Fixed Image::setFormat() sets Image::type instead of Image::format.
Merge pull request #70 from FGM/image-format

Fixed Image::setFormat() sets Image::type instead of Image::format.
Fix leftover array of Edges
Add Sets to CHANGELOG
Use new interface to Sets
Add PR #70 to CHANGELOG
Merge branch 'add-vertices-class' (closes PR #48)

Conflicts:
	CHANGELOG.md
Improve indendation
Merge branch 'master' into improve-minimumspanningtree
Add improved minimum spanning tree to CHANGELOG
Improve test case for 100% coverage