removed unneccessary code
added Validate->between(); for an overview see issue #36
added Validator::even(); for overview see issue #36
added Validator::equal(); for overview see #36
added Validator::multiple; for overview see #36
added Validator::numeric; for overview see #36
fixed README.md
fixed Travis CI link
added Validator::negative; for overview see #36
added Validator::odd; for overview see #36
added Odd Validator
simpified code a lot
version number is displayed when using the CLI
added Validator::perfectSquare; for overview see #36
added Validator::prime; for overview see #36
added one more test to ValidatorTest::testPrime
added Validator::positive; for overview see #36
added extended Error information; Closed #38
applied new assertFailed method to all asserts
added Validator::alnum; for overview see #36