Initial commit.

-- Ported over code from the prrts.c to pRRTstar.cpp
-- prrts.h is no longer needed to compile the pRRTstar.cpp.
-- pRRTstar.cpp now directly uses kd_tree.h and atomic.h.
Merge branch 'portToCpp' of https://github.com/diptorupd/PRRTstar-ompl into portToCpp