Enabled feature where printing ITensor with format string %f shows data.
Changed Opt to use new FLString fixed-length string class for efficiency. Removed Opt operator==. Changed storage of OptSet to std::vector. Moved option.h/cc to utilities folder, along with cppversion.h.
Renamed class Model to SiteSet (keeping Model as a typedef for backwards compability). Renamed models folder to sites.
Fixed comparison operators for FLString class. Added operator+ as an alternative to operator& for OptSet.
Eliminated Index::isNull in favor of inheriting from class safe_bool which allows testing Index as a boolean (implemented through Index::valid() method).
Implemented safe conversion to boolean for ITensor, IQTensor, MPSt, MPOt.
Eliminated Opt::isNull in favor of safe bool idiom (via valid() method).
Removed vector of Spectrum objects from MPSt and MPOt. Considerably lightens amount of data carried by these classes. Added a new method lastSpectrum to DMRGObserver (since DMRGObserver can no longer access spectrum through MPS) and required that Observers used by dmrg routines be derived from DMRGObserver.
Removed some unnecessary methods from MPSt and MPOt.
Updated options.mk.sample, INSTALL.md, and tutorial/project_template to explain new USE_CPP11 features and be easier to follow overall.
Used bcp to add minimal set of boost libraries needed to compile ITensor without C++11. Updated options.mk.sample to automatically include the boost_minimal folder if USE_CPP11=no. Updated INSTALL.md. Also added unittest to folders to clean under make clean target.