Implemented equal
Fixed typo in demo.
Added all overloads for == and !=
Added tests for equal
Added Predicate version for equal
Added tests for predicate version of equal
TODO: 4 iterator version of equal
Made template typenames consistent
Factored push_backs out from unit tests
Merge pull request #15 from r0mai/equal-impl

Two equal implementation plus a bunch of refactoring
Missed an include :(