Add reviewing checklist to docs/contributions. There is some overlap with the style guide. Where the style guide aims to be descriptive, this document is simply a list of questions for the reviewer to ask when when reading a PR.
Merge branch 'master' into review-doc
Merge pull request #441 from waigani/review-doc

Add reviewing checklist to docs/contributions.

There is some overlap with the style guide. Where the style guide aims to be descriptive, this document is simply a list of questions for the reviewer to ask when when reading a PR.
Added organizational aspects.
Merge branch 'master' of https://github.com/juju/juju into api-implementation-guide