v0.11.0

PowerModelsAnnex v0.11.0

Diff since v0.10.0

Merged pull requests:

• Updates for PowerModels v0.21 and JuMP's New NL Interface (#100) (@ccoffrin)

Closed issues:

• Multinetwork Support in OA Objective (#10)
• Extend the QC relaxation (#26)
• Frontend/Defaults (#39)
• Adding transformer tap and angle in frontend. (#56)