v0.2.6

ITensors v0.2.6

Diff since v0.2.5

Closed issues:

• DMRG Not Converging to Exact Result (#725)

Merged pull requests:

• Add support for complex data written by C++ ITensor for block sparse tensors (#724) (@emstoudenmire)
• Tighten accuracy cutoff for OpSum / AutoMPO (#726) (@emstoudenmire)
• Add QNs to Qudit definition as well as Boson alias (#727) (@mtfishman)