v0.16.10

Catlab v0.16.10

Diff since v0.16.9

Merged pull requests:

• Smoothing interaction between VarSets and actual sets and functions (#900) (@KevinDCarlson)
• Fix typo in product keyword arguments (#905) (@jpfairbanks)
• Delete extraneous SigmaMigration method (#906) (@kris-brown)
• Fix Heyting subtraction for ACSets with variables (#909) (@kris-brown)
• Epic backtracking constraint (#910) (@kris-brown)

Closed issues:

• SigmaMigrationFunctor method uses an undefined variable (#903)
• Bug in product keyword arguments (#904)