[subscriber] removing processEvents()

It was bad idea solving potential small value supply races issue

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[subscriber] unsubscribe synchronoulsy

Unsubscribing synchronoulsy to avoid premature unloading of
plugin/library

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[subscriber] resubscribe if can't update

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] statefs::qt namespace for utility fns

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
moving util.hpp to the common includes dir

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] moved to separate .so

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