Changes to the testing framework, additional tests, and fixes. Also a ConnectionPool for irods connections.

Multiple changes in the last week(s):

1. add unit tests for the http frontend and for the storage layer, runnable with nosetests
2. fix issues in the cdmi layer and storage layer that these tests showed
this includes changed behaviour such as MalformedPathExceptions and IsFile/IsDirExceptions
3. implement a connection pool for the irods storage layer
4. support for running automated tests on commit with the travis-ci.