Merge pull request #90 from doug-martin/master

v0.2.13
Merge pull request #91 from doug-martin/master

v0.2.14
Merge pull request #93 from doug-martin/master

v0.2.15
Fixes for constraint creation
Merge pull request #94 from aheuermann/constraint_fixes

Fixes for constraint creation
v0.2.16

* Fixed constraint creation to accept a function when creating or altering constraints.