Deleted all tree balancers.

Benchmarking on a cluster with up to 128 nodes using MPI
showed that the balancing functions did not actually
improve performance or scaling for any number of nodes.
manager --> controller
Now the number of threads is specified as a normal command-line "option".
Removed the adaptive buffer size algorithm.
Now setWorkloadBufferSize is exposed in RequestQueue and an option in MAin.
Fixed package docs module list.
Fixed typo in TUTORIAL.md
Lowered tutorial dependency on transformers to >= 0.2.
Now the tutorials all use setNumCapabilities.
Added tutorial illustrating how to use Main.