v0.6.4

NLopt v0.6.4

Diff since v0.6.3

Closed issues:

• Specifying subsidiary optimization algorithm for augumented Lagranian when using JuMP (#126)
• Unknown status FAILURE (#160)

Merged pull requests:

• Implement local_optimizer for MOI interface (#173) (@blegat)
• Handle missing result status in MOI wrapper (#174) (@blegat)
• Breaking changes for MOI 0.10.0 (#175) (@blegat)