Implement exclusive mode in be_between
Reindent private statement
Refactor the specs and the implementation of the be_between matcher
Change the comment of the be_between matcher
Use __send__ instead of send
Use && instead of and
Add an inclusive method to use the inclusive mode
Wrap the tests in a module
Refactor spec
Merge pull request #412 from pedrogimenez/be_between_exclusive

Implement exclusive mode in be_between