Maven-profiles for hadoop v1 and yarn + default to hadoop_v1 + hbase bugfix

### Maven Profiles
Here is the proposal to add maven profiles to easily switch between hadoop versions (as discussed last friday):
* There are two maven profiles: hadoop_yarn and hadoop_v1 (default).
* Maven profiles can be activated with the -P option
* The default profile will be deactivated as soon as another profile becomes active
* I also introduced a new hadoop.version property, that can be changed using the -D option

How to build for yarn using a specific version (e.g. 2.1.0-beta)
```mvn -Phadoop_yarn -Dhadoop.version=<version>  <goal>```

How to build for any hadoop v1 version (will use hadoop-core):
```mvn -Dhadoop.version=<version> <goal>```

The solution was inspired by mahout and giraph https://github.com/apache/giraph.

### Default to hadoop_v1
Addition from Alexander: The default profile is now hadoop v1 (version 1.2.1)

### pact-hbase Bugfix
Addition from Alexander: Currently the ozone build fails for non-yarn hadoop. Pact-hbase does not work with Hadoop v1 because it uses Yarn classes. To solve this, pact-hbase is excluded if the hadoop_v1 profile is enabled.