Introduced shell script to automatically create issue branches and update pom versions.

Previously every branch push / commit ended up in the same BUILD-SNAPSHOT artefact. In order to avoid potential confusion we now change the pom versions to create issue specific snapshot-builds next to the build-snapshot that is created for the master branch. As an example the version number in SD Commons 1.7.0.BUILD-SNAPSHOT for issue DATACMNS-42 becomes 1.7.0.DATACMNS-42-SNAPSHOT.
This is automatically performed by the new-issue-branch.sh script.

When one begins to work on a ticket just execute:
new-issue-branch.sh DATAMODULE-ISSUENUMBER

E.g.:
new-issue-branch.sh DATACMNS-42 will create a new branch issue/DATACMNS-42 
in SD Commons.