Create testcase for starting builds with RevisionParameterAction

Covering existing behaviour where later builds with different revisions are ignored.
[FIXED JENKINS-15160] Earliest git hash passed by parameter trigger.

Correction is to create a seperate build for each git hash rather than
allowing them to be combined into a single build.
[JENKINS-13368] Merging in change as suggested. Also added a little null
checking for the buildData being passed around now.
[JENKINS-13368] Changing SHA1 of last build to
buildData.lastBuild.revision.getSha1String().
[FIXED JENKINS-13368] Fixed GitAPI so it does both the older style of
checking for changed
files, and used the recommended change.  Added test case for commits to
included files that were changed further back than the last commit.
[FIXED JENKINS-13368] Added one more level of null pointer checking for
new code.
Merge pull request #106 from darthtanner/master

[JENKINS-13368] Fix for missing changes if multiple commits back.
[JENKINS-15160] add support for combining git hashs when passed downstream

Don't combine with manually started builds
Merge pull request #107 from cjo9900/JENKINS-15160

Jenkins 15160
Add ability to update tag. #JENKINS-15758
Merge pull request #109 from vkravets/master

Possible fix fo JENKINS-15758. Add ability to update tag.
JENKINS-15083 Avoid rebuilds upon intermittent network failures and similar
Merge pull request #110 from krosenvold/master

fix for [JENKINS-15803]
java.awt.headless=true for unit test, too much coffe on osx :-)
use a more recent version of release plugin
[maven-release-plugin] prepare release git-1.1.26
[maven-release-plugin] prepare for next development iteration
Fix reset and init for new repository

Fixes JENKINS-15432
Merge pull request #111 from rolandschulz/master

Fix reset and init for new repository
add version field to support new GitLab URL-scheme