Update DesiredCapacity if AutoScalingGroup.desired_capacity is not None as fix for boto/boto#1757
Use appropriate unittest assertions for instance types in autoscaling tests
Add tags to EMR cluster object, implement remove tags call, add a test for removing tags.
Merge pull request #1928 from danielgtaylor/emr-update

EMR Service Update (Tags). Fixes #1928.
Merge pull request #1906 from oxtopus/issue-1757-update_desired_capacity

Update DesiredCapacity if AutoScalingGroup.desired_capacity is not None. Fixes #1906, #1757.
Switched all classes over to new-style classes.

Fixes #1918.
Whitespace removal.