Added tag support to Volumes and Snapshots. Re-factored tag functionality in AMI/EC2 and moved some common code to AWSCloud.
Merge branch 'develop' of https://github.com/clstokes/dasein-cloud-aws into develop

Conflicts:
	src/main/java/org/dasein/cloud/aws/compute/EBSSnapshot.java
	src/main/java/org/dasein/cloud/aws/compute/EBSVolume.java
	src/main/java/org/dasein/cloud/aws/compute/EC2Instance.java