2.8: Git Checkout: Replace CleanBeforeCheckout by CleanCheckout

It looks like scm polling is interfering with running build :-/

2.7: Make StashId unique

Fix uniqueness of StashId

2.6

Remove default job trigger allowing to manually configure trigger.

2.5

Fix git subtree checkout - need slash at the beginning

2.4

Improve mvn.log: Add full command line
Timeout for Activities.

2.3

Graph logic refactored; default excludes for StashActivity can be disabled.

Fixes and small improvements

Fixed git support
Listener for Checkout

Improved configurability and more

Merge pull request #2 from shasait/develop

Integrate changes from develop

First release after concept refactoring

Used in production.