Continuuity Tephra 0.2.1

This release fixes the following issues:

• TransactionProcessor use of FilterList on flush and compaction causes abort
• Support coverage report generation
• TransactionProcessor should use TransactionVisibilityFilter on flush and compact
• Cleanup class and package names
• Use Configuration instead of HBaseConfiguration when possible
• TransactionVisibilityFilter should support additional filtering on visible cells
• Assigned transaction IDs should reflect current timestamp
• Remove using of HBase Bytes in non-HBase related classes in tephra-core

Please note that a number of the Tephra packages and classes have been renamed for clarity. Any existing code will need to be updated.