Use demension supplied by the user

If the user specifies dimensions for either the height or width of a
node or edge we use that instead of the bbox value we derive when we
render the label for the node / edge.
Prep v0.2.1 release
Bump version and set as pre-release
Merge branch 'master' of git://github.com/PaulKlint/dagre-d3 into PaulKlint-master

Conflicts:
	lib/Renderer.js
Fix height handling
Code style consistency
Fix read of stroke-width attribute
Fix attr read for ry and only use rx / ry if they're set
Add CHANGELOG entry / credits for v0.2.2
Prep v0.2.2 release
Bump version and set as pre-release
Revert to using attr for fill

I've tested this on Chrome and Firefox. In both cases, fill color is set
by one of the following rules, in order of highest to lowest priority:

1. Fill is defined in the style attribute
2. Fill is an attribute itself

When we switched fill to a style it breaks the application of CSS rules.
By leaving it as an attribute, we get a default of a white background,
apply any CSS rules, and then override those rules only when 'fill' has
been set on the node itself.
Prep v0.2.3 release
Bump version and set as pre-release