Made some changes to JoystickReader for third robot.

Changes are by no means finalized!

- Copied input stuff to bot3/input.
(Copying even unmodified files was necessary so git wouldn't build stuff
from frc971/input/input.gyp and see duplicate targets.)
- Modified build system to build this.
- Took the opportunity to fix some name-related stylguide compliance issues.
(I fixed these in frc971 as well.)
13 files changed