v0.13.1

Convex v0.13.1

Diff since v0.13.0

Closed issues:

• Rethinking how to approach v0.13 (#361)
• [Request] Ability to suppress "vexity check" warnings (#362)
• No speedup from multithreading. big speed up from multi-processing (#370)

Merged pull requests:

• Pass solver constructors instead of instances (#368) (@ericphanson)
• export Constraint (#371) (@ericphanson)
• Allow disabling DCP warnings (#372) (@ericphanson)
• Update for v0.13.1 (#373) (@ericphanson)
• Switch atomics to refs (#374) (@ericphanson)