Added tag support to Volumes and Snapshots.
Merge branch 'develop' of https://github.com/clstokes/dasein-cloud-core into develop

Conflicts:
	src/main/java/org/dasein/cloud/compute/SnapshotSupport.java
	src/main/java/org/dasein/cloud/compute/Volume.java
	src/main/java/org/dasein/cloud/compute/VolumeFilterOptions.java
	src/main/java/org/dasein/cloud/compute/VolumeSupport.java