1) Cleaning the code
1.1) Replaced scoped_ptr with unique_ptr
1.2) Introduced shared_ptr in a couple of places
2) Now using the standard C++ number generator
3) Moved all distance/correlation functions to distance_*.cc files
4) Fixed a bug with computation of SpearmanRho. Fortunately,
it did not appear if the number of pivots was a factor of 4.
5) Carefully introduced #ifdef to make the code compilable without
SIMD extensions.
6) Added a generic LP space and implemented its several efficient
implementations
7) Revised unit tests and add new tests, in particular, for rank
correlation functions.