De-duplicate variable definitions

By having the variable definitions in only one place, it should get easier to
add additional monitoring variables.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Capitalize monitoring variable descriptions

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Reverse wires on motor #1

We don't know why these changed.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Switch to signed variables, add power and speed

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>