Split libinput contexts into udev/path classes

[whot]

Since python is supposed to abstract this nicely, better than C anyway you should have a

class LibInput:
   # almost everything

class LibInputUdev(LibInput):
   # the few udev functions

class LibInputPath(LibInput):
   # the few path functions

And then maybe a Libinput.context(ContextType=UDEV) (see #1) that returns the right object. This way you don't have a path_foo() function on a udev context and vice versa

[OzymandiasTheGreat]

This would be less error prone, will do.