Changed getObservations result

The result is now a list with three data.frames. One containing the
casted observation-data (subject.id ~ conceptName), and the two other
containing all meta-data relating to subjects and concepts.

In addition, the dependency on the reshape package has been added.
Merge branch 'transmartRClient' of https://github.com/thehyve/RInterface into transmartRClient

Conflicts:
	transmartRClient/DESCRIPTION