Changed dependencies to 4.13.0
Added missing method
Remove open ended rake requirement
Allow versions 4.12 and 4.13
Added note about past_version potential
Updated README that we support 4.12 & 4.13
Use tag for fdbsql-4.13.0
Merge pull request #8 from ScottDugas/4.13.0

Support for sequel 4.13.0