Added surrounding_indices() and change_dimensions().
Added set_canonical() and canonical_form().
Extended all_equal() to compare also with numbers.
Added operator&& and operator! for Booleans
Added templated class Arpack
Add missing prototype for sparse-tensor multiplication
Added back cdmrg.cc. Fixed the last names and type conversions in dmrg.cc
Added function normal_form() for MPS, which is just a canonical form normalized.
Added the most basic MPS time evolution algorithms.
tensor::reshape is no longer a template to allow it working with views (implicit coercions are not considered when using templates)
Removed certain uses of negative dimensions (tensor currently does not support them).
Added a minimal test for TimeSolver
Implemented split_interactions()
Fixed prototypes and typos in set_canonical() and canonical_form()
Increased the set of tests for the RefPointer object
Code cleanup in RefPointer: functions which are only used once are inlined manually and unused methods are removed.