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.)
diff --git a/frc971/atom_code/atom_code.gyp b/frc971/atom_code/atom_code.gyp
index 9a111b0..99f7047 100644
--- a/frc971/atom_code/atom_code.gyp
+++ b/frc971/atom_code/atom_code.gyp
@@ -17,8 +17,8 @@
         '../control_loops/shooter/shooter.gyp:shooter_lib_test',
         '../control_loops/shooter/shooter.gyp:shooter',
         '../autonomous/autonomous.gyp:auto',
-        '../input/input.gyp:JoystickReader',
-        '../input/input.gyp:GyroReader',
+        '../input/input.gyp:joystick_reader',
+        '../input/input.gyp:gyro_reader',
         '../../vision/vision.gyp:OpenCVWorkTask',
         '../../vision/vision.gyp:GoalMaster',
         '../output/output.gyp:MotorWriter',