For actionview4.0.0.beta1 fix, missing require file

/home/travis/build/sanemat/actionview-link_to_blank/test/test_actionview-link_to_blank.rb:11:in
`<class:TestActionViewLinkToBlank>': uninitialized constant
TestActionViewLinkToBlank::ActionDispatch (NameError)
For development
Pass actionpack v4.0.0.beta1
Merge pull request #3 from sanemat/feature/rails4

Adjust actionpack v4.0.0.beta1