Updated README for 2.2.0 release.
Merge pull request #1 from jvwag/master

Renaming of MuniZigbeeException -> ZigbeeException
Minor reorganisation and indent fixing
Removed unimplemented clusters from the Cluster enum
Fixed indenting and reduced complexity of the ClusterFactory, added unittests
Work in progress on the Node Descriptor
Merge pull request #1 from munisense/master

Merge from upstream