v0.6.1

DisjunctiveProgramming v0.6.1

Diff since v0.6.0

Merged pull requests:

• MBM update (preparation for InfGDP) (#133) (@dnguyen227)
• Cutting planes update (Prep for InfGDP) (#134) (@dnguyen227)
• Extensions to MBM and cutting planes techniques. (#135) (@dnguyen227)