1.5.1

• Improvements to documentation (scottclowe).
• Improved code linting by reworking private variables in Rule class to now be properties and updated
  all code that used the old way.
• Improved code linting by reworking all Log messages to render according to pep standard.
  (By using %s and passing in variables as positional arguments)
• Fix bug when validating sequence and value should only be unicode escaped when a string
• Improve validation of timestamps.
• Improve float validation to now accept strings that is valid ints that uses scientific notation, "1e-06" for example.
• Update travis to test against python 3.6