Fix stream command tests
- Fixed stream list assertion to check if they exist in the stream list rather than checking at index '0'
  (This will avoid the tests' dependency in running on clean redis store)
- Refactored stream tests assertions
Fix tests on jdk6
XD-534 Add shell integration tests for tap
Added tests for tap commands create, deploy and destroy
Added AbstractTapIntegrationTest class that has tap commands execution methods
Fix Tap commands result text
Added util httpPostData method for 'http post'
Added util checkIfCounterExists method for verifying counter existence
Fixed StreamCommandTests & NamedChannelTests to use httpPostData() for 'http post'
Fix executeStreamCreate() to add stream before assertion
Add counter value check to verify the stream with counter sink
- Added counter delete support at CountersController
- Added shell command for "counter delete"
- Updated tests to check for counter value
Move delete() to AbstractMetricsController