This function will clear the current keyboard and mouse states.
Note that what happens in the next step after calling this function
will depend on what is being checked and the platform it is being
checked on. With mouse input, the mouse button will have to be
released and pressed again for any further input to be detected,
but with the keyboard it's not quite that simple. In general, the
keyboard will be cleared only for that step but the next
step will again detect the key, however this may not be the same
across all platforms and keyboards, and in some cases the function
may act like it does for the mouse and require the key to be lifted
and pressed again.
This will clear all keyboard and mouse states.