XD-472 XD-473 Adding support for multiple Hadoop distros

Adding a startup option  --hadoopDistro for server 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

Adding spring-xd-hadoop distro specific sub-projects with the
following distros:

- hadoop10 - Apache Hadoop 1.0.4

- hadoop11 - Apache Hadoop 1.1.2

- hadoop20 - Apache Hadoop 2.0.5-alpha

- phd1 - Pivotal HD 1.0