XD-473 Improving command line argument access

Making the command line argument access compatible
with all environments supported by the batch script
XD-579 Adding support for multiple Hadoop distros in XD shell

Adding a startup option  --hadoopDistro for XD shell scripts.
The default is hadoop10 (Apache Hadoop 1.0.4). Based on the
default or passed in distro we will add the correct jars to the
classpath
XDd-576 Change prompt of shell to xd:>
XD-587 Controllers now inherit from a base class for boiler plate code.

Get rid of boilerplate code.

Adding list to command

Now supporting Save command in XD Controller

Triggers now use XD-Controller

TapController is now using XD Controller.

Save now does a parse before "saving".

Added copyright and cleaned up the code.
Merge branch 'XD-473B' of https://github.com/trisberg/spring-xd into trisberg-XD-473B
Fix marshalling of metrics resources; Still pending json as default
Use json as default Accept'd media type + hack for xml JAXBContext initialization