Provide features for working with groups

[jamesscottbrown]

OVE now supports groups, and operations on all of the sections in a group.
Support for working with groups should be added to the Python library.

[jamesscottbrown]

The API currently allows a group ID to be provided as an argument to /moveTo and /transform.

However, I'll wait until ove/ove#124 is resolved before adding groups to the Python library.

[senakafdo]

@jamesscottbrown you can proceed with the implementation of the Python API. I believe that the confusion here was because the API documentation was not clearly stating that this operation only deletes the group and not the sections within it.

As creating a group is separate to creating sections and because a given section could (if needed) be in more than one group, the deleting of a group does not semantically support the possibility of deleting the sections within it. I wanted to note this so that the Python SDK remains consistent with the design of OVE core.