Debugged ZigzagPersistence (having added heavier consistency checking) * Added DEBUG_CONTAINERS option (uses std::__debug::* containers for chains and in ZigzagPersistence) * Added SizeStorage specialization for std::deque<T> * ZigzagPersistence got a lot more consistency checking (in debug mode only, which now crawls); as a result it's been debugged (running on non-trivial examples) * examples/rips/rips-zigzag takes command-line options * added ChainWrapper::clear() * added Simplex::VertexDimensionComparison * added PairwiseDistances class (for computing distances between points in a container according to a distance functor)

Write an audit for the data structure.

-DBOOST_UBLAS_TYPE_CHECK=0 is necessary since otherwise Boost's uBLAS gives a compile-time error 
when it doesn't find sqrt for polynomials. It doesn't actually need it (e.g., for LU-decomposition, 
but it looks for it during type check). (File a bug report with Boost?)