[property] pass shared_ptr with setter

Otherwise it is possible to code logic when update() can be called after
property has been deleted

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
statefspp and inout refactoring

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[api] Basic Writer is taken from inout

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[config] Tracing dumping/registration

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[api] update property only if it was changed

also notify poll only in this case

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

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] some c++ utility functions

Functions purpose is to work with default statefs paths

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[power-emu] power emulation inout provider

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[config] skip non-existing library

If provider/loader does not exist, ignore it. It solves issues if
library was removed while not unregistered

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