Use vehicle_data api (BC)

[andig]

Fix https://github.com/bogosj/tesla/issues/97

This PR uses the remaining vehicle_data api and renames StateRequest (which never was a request) correspondingly.

TODO:

• [x] test
• [x] fix tests
• [x] examples
• [x] login

[andig]

From what I could tell:

• all getter apis combined into one
• all data always available (no more pointers)
• servicedata no longer exists, hence removed (?)

Working according to my tests.

/cc @bogosj could I get an additional confirmation?

[bogosj]

LGTM

[tijszwinkels]

Works well in my tests. Thanks for quick turnaround guys!