v0.1.31

ITensors v0.1.31

Diff since v0.1.30

Closed issues:

• IndexSet docs are outdated and need more details (#541)

Merged pull requests:

• Add Ising YY and ZZ gates (#539) (@anupam-mitra)
• Introduce splitblocks function (#540) (@mtfishman)
• Add flux of IndexVal functionality (#543) (@mtfishman)
• Improve contractions involving scalar-like ITensors or blocks (#545) (@mtfishman)