Version bump (#30)

Merge pull request #21 from ryanjoneil/require-ruby-2.4

switching to ruby 2.4.0

Merge pull request #20 from ryanjoneil/gh-docs

docs and version bump

Merge pull request #17 from ryanjoneil/examples-and-docs-v0.2

Adding UFL example. Fixing issue with constraints of the form "x <= y".

Merge pull request #16 from ryanjoneil/support-scip

Support scip

Merge pull request #12 from ryanjoneil/support-cplex

Support cplex

Merge pull request #8 from ryanjoneil/cbc-and-clp

Adds cbc and clp

Adding simple examples