First attempt at parallel execution using timestampts to track execution progress

A task reading from queue, executing, evaluating and writing to output
queue is started in each available scheduler. ManualResetEvents are used
to wait for completion
TestExecutor should use all the available schedulers
Removed unnecessary extra lock
Refactored common code in ExecutePar and ExecuteSeq into a new function
Added Stopwatch to track execution times
Updated input/output stubs to allow better execution time checking
New test parameters are now written to new parameter file
First step of phasing out the TestCaseParameter class and InternalParamterHandler

SQLQuery now only have one set of test case parameters, stored as
properties in the test object, not using the TestCaseParameter class