Create new project proposal: IGitt scm support

[jayvdb]

IGitt is a library to support multiple hosters.

coala bears for VCS currently do not use IGitt. They should. However coala bears support BitBucket (git and mecurial), and BitBucket support is missing from IGitt.

The first goal of this project is to add BitBucket (git & mecurial) support to IGitt and convert the coala-bears to using IGitt.

Gerrit and Phabricator support are two other git hosters which are important for IGitt adoption into large OSS orgs. These should be added in the second phase.

Then the third phase of the project is to add two more non-git scm, such as fossil and launchpad.

[jayvdb]

The pre-requisites could be

• an enhancement to the coala VCS bears
• an enhancement to IGitt

Additional recommended preparation tasks:

• enhancement to https://github.com/guyzmo/git-repo