Updated roadmap

New exactApplyMPO algorithm with better scaling (m^3k^2+m^2k^3) and l…

…ess ad hoc approach to compression of resulting MPS

Version 2.1.0 release of ITensor

Added optional names S+ and S- to tJ site set

factor function now returns Spectrum object resulting from svd

Added some comments to options.mk.sample about Windows and Intel C++ …

…compilers

Removed unused variable in eigensolver.h

Changed error behavior of findIQInd to return default IQIndex instead…

… of throwing.

New unit test for .apply for Diag storage

Very minor edit to autovector.h