Issue #1728 Request Queue Size via REST

This allows the size of a distributed queue to be returned via the REST
API.
Add tests for queue size rest API.
Allow RequestWrapper.RequestDispatcher to use the provided servletRequest

Currently, the RequestDispatcher that's returned by RequestWrapper always passes
the RequestWrapper to the wrapped RequestDispatcher instead of the request that
was provided to the forward or include method. This prevents a caller from
providing a wrapper of its own; the provided wrapper is ignored by the
RequestDispatcher.

The current behaviour is presumably a defensive move to prevent callers from
passing in the unwrapped request and thereby 'escaping' the wrapper that
provides the distributed HttpSession. There is no need for this because:

* if the caller has access to the unwrapped request, he can already break
  the distributed HttpSession
* if the caller does not have access to the unwrapped request, he can't
  break the distributed HttpSession either.
* Disabled backup operation scheduling, not needed since backup replicas are synced by partition updates.
* Fixed backup replica version calculation during backup op send.
* Fixed backup replica index calculation.
* Limited parallel replica sync operations.
* Removed problematic test marker from BackupTests.
checkstyle fixes
Fixes #1949. Introduced TraceableOperation interface for operations those off-load their execution and terminate, like executor service operations.
Merged with latest master bracnh
Merged with latest master bracnh
test fix
minor test fix
throw RejectedExecutionException
invocation concurrency fix
cleanup
Merge pull request #2000 from gurbuzali/client-execution-invocation-fix/3.2-RC3

throw RejectedExecutionException
fixes testMapWithIndexAfterShutDown
fixes testMapWithIndexAfterShutDown
fixes testMapWithIndexAfterShutDown
eviction test fixes
minor doc fix
Merge pull request #2002 from ahmetmircik/queryTestFix

Fixes issue #2001
Merge pull request #2003 from enesakar/eviction-test-fixes

eviction test fixes
fixes testHighConcurrentLockAndUnlock