Fix `Cell.rails3_1_or_more?`, `Cell.rails3_2_or_more?` and
`Cell.rails4_0_or_more?` methods
Merge pull request #179 from kuraga/patch-2

Fix `Cell.rails3_1_or_more?`, `Cell.rails3_2_or_more?` and `Cell.rails4_0_or_more?` methods