#56: Add support for Python 3.

Applied 2to3.
#56: Add support for Python 3.

Updated trove classifiers.
Disabled Travis build because for the foreseeable future they will fail.
We changed the layout of a range from "1:5" to "1...5".
#62
#62 Modified comments
#60 validate function
#60 implemented set_properties and unittests
#60 Bugfix
#60 fixed set_property
#60 Cleanup
#63
#63 Implemented Unit Tests
#63 Implemented Unit Tests
#60 implemented unit tests and bugfixes (validate, set_property)
Merge remote-tracking branch 'origin/htlwrn' into htlwrn
#58: Moved RangeError and some helper classes to errors module.
#58: Added data format errors.
#57: Fixed relative import errors when run from PyCharms by adding a proper project.
#64