Centralized test suite for the Escher lib.

You can export these tests easily to the test folder using SVN. This works on Travis CI.

svn export https://github.com/emartech/escher-test-suite/trunk/test_cases DESTINATION_FOLDER

Usage example can be found in Escher-Ruby.

Don't forget to create a test that checks whether all test cases have been run from the test suite. Otherwise we lose the purpose of this centralization.