ITensor version v1.0.0

This release adds a number of new features and makes some overdue breaking changes to the library. For detailed information, view the change log.

Some notable changes include:

• Put all code into namespace itensor
• No more dependence on boost library when compiling with USE_CPP11=yes set in options.mk.
• Minimal boost header code included with library download when compiling with USE_CPP11=no.
• Removed ITSparse and IQTSparse classes. Now ITensor carry an internal sparse-mode flag.
• MPS class no longer stores accuracy parameters (maxm,cutoff,...) or a vector of Spectrum objects.
• MPS class no longer defines + and += operators. Use functions sum and plusEq instead.
• Improved methods for constructing OptSet named argument sets.