December updates

This release has some interesting updates:

• Update of sensiolabs/security-checker by @arjank
• Extra test for the undefined SOAP_1_2 constant warning (issue #60) reported by @gasperkol
• Adding Docker containers to make testing a whole lot easier (documentation will follow soon)
• Removal of dead code

Many thanks to all for helping me improve this package. I wish all of you happy holidays and a wonderful 2019!

Michelangelo