[Fix JENKINS-16737] and [Fix JENKINS-10434] - no exception if author not found

Return unknown user rather than throwing exception in GitChangeSet

Refer to [JENKINS-16737] and [JENKINS-10434] for two cases where a
GitChangeSet cannot find an author and throws a RuntimeException when
it would be much better to report an unknown user and allow execution
to continue.

Added a Polish character to the accented character test

Use more diacritics in the latin accented character test

Use parameterized GitChangeSet test to better cover cases
Remove timezone dependent GitChangeSet test assertions
Minor improvement to GitChangeSetSimpleTest
[JENKINS-23641] - Annotate BuildData::getLastBuiltRevision()

Signed-off-by: Oleg Nenashev <o.v.nenashev@gmail.com>
Fix findbugs warning exposed by preceding findbugs CheckNull annotation
Update JGit to 3.5.1
Pass marked revision to decorateRevisionToBuild()
[FIXED JENKINS-25191]
Merge pull request #261 from wannessels/fix-25191

Pass marked revision to decorateRevisionToBuild()
Update dependency to promoted-builds 2.19
Update dependency to mockito-all 1.10.8
Update dependency to ssh-credentials 1.10
Update dependency to joda-time 2.5
Update dependency to credentials 1.17
Update dependency to git-client 1.11.0

First git-client version to include JGit 3.5.1
[FIXED JENKINS-22400] option to set submodules update timeout

Cherry pick from 7dab96f8b5b1ea95e3a92123e6424376d7fa1036
Update credentials dependency to 1.18
Update mockito dependency to 1.10.9
[Fixed JENKINS-25313] fix null pointer exception when last repo or branch deleted
Update mockito dependency to 1.10.10
[Fix JENKINS-25313]  avoid null pointer if repository not defined