Fix possible NPE and aloow to change Beaker URL

When beaker builder is installed for the first time, beaker server URL is not setup and therefore beaker client is not setup (is null).
Later on, when URL is setup in main config, beaker client is not recreated for that to get rid of null, Jenkins has to be restarted.
Also when one want to change Beaker URL, it's not changed and Jenkins needs to be restarted.
[maven-release-plugin] prepare release beaker-builder-1.2
[maven-release-plugin] prepare for next development iteration
Ad possibility to expand job path

It's quire common scenario that job XML is different for e.g. various ditributions so that matrix jobs can be hardly used. When job XML
path is can be expanded, this solved the problem, as job each matrix axis can have different job XML.
[maven-release-plugin] prepare release beaker-builder-1.3
[maven-release-plugin] prepare for next development iteration
Bump beaker4j version
Add possibility to download log files
[maven-release-plugin] prepare release beaker-builder-1.4
[maven-release-plugin] prepare for next development iteration
Bump beaker4j version nd thus fix possible NPE
[maven-release-plugin] prepare release beaker-builder-1.4.1
[maven-release-plugin] prepare for next development iteration
Fix typo