Usergrid 2425 remove jarclassloader

This pull-request removes JarClassLoader, fixes problems with UG startup on Mac OS and more. Here are the specific changes:

1) Eliminate the need for the GPL licensed JarClassLoader class (in both standalone and launcher) by using the Maven dependency plugin's unpack dependencies option to create one jar with all dependencies expanded instead of a jar of jars as we had before. To prevent META-INF files from colliding we exclude them, and include our own set of files that aggregate the values found in the ones we exclude.

2) Fix startup and database retention problems on Mac OS by excluding Snappy 1.0.4 from the Cassandra dependency and directly including Snappy 1.0.5 as a dependency.

3) Exclude the test user account from the activation / confirmation flow.