Added unit tests for filesystem and tracing.

Some corrections in the unit testing facility.

Adjusted for a change in singletons names from dynamicgraph.

Changed order of compilation of some .cpp files to prevent mysterious Segmentation Fault(s) from appearing.

* Added #ifdef VP_DEBUG to sot-h.cpp
* The code inside the #ifdef VP_DEBUG of sot-h cause a segfault if ever compiled in every program using the library. Leaving it that way before full-scale tests and validation.