COMP: Add wrapping for ThreadPool and ThreadJob

Fixes the following warnings:
build/Wrapping/Modules/ITKCommon/ITKCommonBase.xml: warning(4): ITK type not wrapped, or currently not known: itk::ThreadPool
build/Wrapping/Modules/ITKCommon/ITKCommonBase.xml: warning(4): ITK type not wrapped, or currently not known: itk::ThreadJob

Change-Id: I09b939f828dfbba5bcddebf92a567003fba74268
COMP: Remove unimplemented DestroyPool method

In the parent patch (http://review.source.kitware.com/#/c/16485/), we found out that DestroyPool()
is not implemented. I removed it as it seems not to be needed.

Change-Id: I34f59520c44a2bacf533eb2fd4f27ffd1e32dda5
Merge topic 'WrapThreadPool'

3bf89243 COMP: Remove unimplemented DestroyPool method
5fef9e68 COMP: Add wrapping for ThreadPool and ThreadJob