.gitignore: Added UNIX-style backup files (*~)
input: Added axis-only controller impl. using Linux `evdev`

  * TODO: add button support, and separate the platform-specific
    driver code into a subclass of `Controller`.

Note that the controller code is currently untested (though it
compiles and is based on code that was working last year...)
Merge remote-tracking branch 'dubotics/master'
README: I guess I'm a contributor now, huh?