ximcp: Unmake to fabricate key events with XKeyEvent serial
_XimProtoKeypressFilter() and _XimProtoKeyreleaseFilter() can receive XKeyEvent from both the typing on the keyboard and the callback of XIM_FORWARD_EVENT.
If the filter functions unmake to fabricate XKeyEvent from the typing on the keyboard during receiving XKeyEvent from the callback of XIM_FORWARD_EVENT with typing keys very quickly likes an bar code scanner(evemu-play), XIM server cannot receive some key events and it causes the key typing order to get scrambled.
Now XIM client has an array to save serials in XKeyEvent and the filter functions unmake to fabricate XKeyEvent from the callback of XIM_FORWARD_EVENT only.
Fixes: #198 (closed)