[SCM-750]: support TFS checkin-policies

https://jira.codehaus.org/browse/SCM-750 : 
In TFS, there is an option of "checkin policies". In this case, whenever a developer checks-in his code, another dialog pops-up , and asks to enter a comment. I really do not know who really uses this feature and actually enters a real comment (since the comment that is related to the check-in was entered in a previous dialog), but in my case the organization's SCM forces this extra-dialog. The problem: when I try to check in a file using a command line, I HAVE TO add an extra argument to the command (see example below). Hence, the scm-tfs plugin does not work, since it lacks this 'extra' argument. As far as i saw the code, I understand that the command is hard-coded, and unfortunately it is not configurable,
This is an example command-line for check-in (only a single pom.xml):
tf checkin -noprompt "-comment:[maven-release-plugin] prepare release some-comment-for-checkin" D:\.....\pom.xml /override:";Auto-Build: Version Update";
in this example, '/override:";Auto-Build: Version Update";' is the extra-argument.