https://issues.jenkins-ci.org/browse/JENKINS-3002 - Implemented ability
to checkout by label.
Corrected missuse of tfs sdk.
Changes proposed by the code review.
Merge pull request #24 from kopcheski/master

JENKINS-3002 Support GET by TFS label
[FIXED JENKINS-23033] don’t use String but Secret to store password
UI binding will use a cipher and avoid it to be exposed as plain text in HTML form.
fix test suite, 
need to run within a test instance, as Secret rely on Jenkins.getInstance().IdKey
Better use of UI binding
Updated Ignore
Merged to the latest repo
Merge branch 'master' of https://github.com/DD202/tfs-plugin

Conflicts:
	.gitignore