state: use stdbool in filters

Signed-off-by: Ran Benita <ran234@gmail.com>
keyseq: add a couple of tests

Tests the filter refcounting.

Signed-off-by: Ran Benita <ran234@gmail.com>
rules: quiet a gcc warning

src/xkbcomp/rules.c:620:36: error: 'idx' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Can't happen but no harm done.

Signed-off-by: Ran Benita <ran234@gmail.com>