Update to correspond to Tesla's new REST API

[jpasqua]

Tesla has changed their REST API including the way that authentication is performed. This task is about updating to their new API. This will result in API changes to TeslaClient that will require (fairly mechanical) changes to clients.

[kgoderis]

Hi - I am an active contributor to the openhab.org / eclipse smart home projects. Would you be open to integrate your work into these projects? you can ping me at karel.goderis [AT] me.com

[jpasqua]

I've responded directly to karel.goderis [AT] me.com, but to reiterate for others, please feel free to integrate this code into any projects you'd like. It is shared under the MIT license and of course comes "as is" with no warranty. HOWEVER, please be aware that use of this API is not sanctioned by Tesla and may cause adverse effects.