Refactored connection_open function.
Update .travis.yml
Further pep8 refactoring.
Refactored connection_close function.
Correcting syntax error:

************* Module pyrail.controllers.hornby
E: 57, 0: invalid syntax (syntax-error)
Refactoring connection_close function.
Refactoring set_debug function.
Refactor parity function for PEP8 compliance.
Refactring send function for PEP8 compliance.
Additional PEP8 compliance checking for send function.
Refactor constructor for train class.
Refactor throttle method in train class for PEP8 compliance.
Refactoring tain classes' function method for PEP8 compliance.
Complete refactoring of train class for PEP8 compliance.
Refactoring accesories class constructor for PEP8 compliance.
Complete refactor of accesories class for PEP8 compliance.
Refactor - Fixing variable names for pep8 compliance.
Refactoring for PEP8 compliance.
Removing single letter variable names for PEP8 compliance.
Resolving multi statement per line issues for Pep8