[subscriber] using separate thread for polling

Properties are monitored in a separate thread because during animation
main thread polls 'em frequently

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[subscriber] dropping qt4 version

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
register.c is generated

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>