0.2

Add FacturaeRoot signature functionality
- New methods
  - FacturaeRoot.sign(pkcs12_cert, password) to sign a FacturaeRoot instance
  - FacturaeRoot.sign_verify(signed_root) to verify the already created signature
Add basic signature tests with a dummy self-signed cert
Provide Travis-CI integration to validate tests and autodeploy to Pypi on tag
Fix Special Taxable Event Reason attribute name #5

0.1.0