turn FTSFromVertexToPointFactory::operator() into a static method

FTSFromVertexToPointFactory does not have any data members, and a single (currently non-const) method, FTSFromVertexToPointFactory::operator() .
This patch changes that single method into a static method, FTSFromVertexToPointFactory::get(), and propagates the change to downstream code.
Made SimpleMemoryCheck thread-safe

Switched SimpleMemoryCheck to use the new Service APIs. In addition, switched to using std::atomics for thread safety. The module was changes so that if a callback is made while another callback is updating the memory measurement, the second callback just returns immediately.
Declare constant statics const
Remove superfluous const
Merge pull request #1214 from wmtan/DeclareConstantStaticsConst

Multithreading fixes -- Declare constant statics const
Merge pull request #1213 from Dr15Jones/threadSafeSimpleMemoryCheck

Multithreading fixes -- Made SimpleMemoryCheck thread-safe
Merge pull request #1203 from fwyzard/make_FTSFromVertexToPointFactory_static

Multithreading fixes -- turn FTSFromVertexToPointFactory::operator() into a static method