Install a new compressor

Install a new compressor

A brand new event compressor based on Kuba Ober's cleverly simple
solution: <https://stackoverflow.com/a/21006207>.

Fix #9362, #9461, #9933: Lyx suddenly gets keyboard keys wrong, and
deadlocks

Fix #9790: LyX should perform key event compression (for improving the
remote X connections one would also need to implement
Qt::WA_KeyCompression)

Fix #10516: slowness on repeated arrow keys with IBus and Qt5

Patch pulled from
https://github.com/gadmm/lyx-unstable/commit/bf5a1efb0db5bfc2b

Signed-off-by: Juergen Spitzmueller <spitz@lyx.org>