Added sparse checkout option
Fixed Checkout command to act as the previous checkoutBranch method
Changed git client dependency version with the released one 1.6.6
Document and improve test for building a sha1 rev

The 'branch to build' option already also accepts a SHA1-hash to specify
the specific revision to build, but this was not really obvious (neither
in the online help nor in the code). Added a note to the documentation and
a test which covers part of this functionality more explicitly, though part
of this still happens in GitSCM which isn't really under test.

See also JENKINS-22278
Merge pull request #219 from raboof/master

Document and improve test for building a sha1 rev
filterTipBranches: Use O(n) instead of O(n^2) algorithm.

Fixes JENKINS-5724.

Before, this made slaves run on 100% CPU for days when idle.

This makes it a few thousand times faster for a repo with 500 branches.
Merge pull request #156 from nh2/fix-filterTipBranches-performance

filterTipBranches: Use O(n) instead of O(n^2) algorithm.
Merge pull request #215 from Tetradeus/sparse-checkout

Added sparse checkout option
Update to JGit 3.3.0 and other more recent versions

This intentionally updates to JGit 3.3.0 even though JGit 3.3.1 is now
available.  The git-client-plugin still uses 3.3.0 and the git-plugin
should not depend on a newer version than the git-client-plugin.

Once the git-client-plugin updates to 3.3.1, git-plugin may update also.
[maven-release-plugin] prepare release git-2.1.0
[maven-release-plugin] prepare for next development iteration
Remove outdated dotm2_settings.xml file at root

Jenkins infrastructure has improved since 5 years ago