Improved documentation for cactiStyle

Explained possible options for system (not letting the reader hunt around for
possible values), as well as culled most info for alignment from:
https://github.com/graphite-project/graphite-web/issues/671
Improved documentation for areaBetween
Merge pull request #842 from ojilles/0.9.x

0.9.x backport of documentation updates
Minor fix for Vagrant+Syntesize docs
Allow metric finder to return jsonp objects

Needed for cross-domain ajax calls

Fix jsonp response format
Documenting that you can use alpha values for colors in colorList and bgcolor.
Merge pull request #845 from deniszh/0.9.x_doc_fix

Minor fix for Vagrant+Syntesize docs, backport pull request 844 to 0.9.x.
Merge pull request #847 from ojilles/0.9.x

Documenting that you can use alpha values for colors in colorList and bg...
Backport of pr #495 to 0.9.x branch

Fixes issue #220
Merge pull request #851 from deniszh/0.9.x_HWA_fix

Backport of pr #495 to 0.9.x branch
Merge pull request #846 from kali-hernandez-sociomantic/jsonp

Allow metric finder to return jsonp objects
Merge pull request #45 from graphite-project/0.9.x

Pull in Upstream Changes