[tests] testing joining of options

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[mt] wrap wrong gcc-4.6 future::wait_for retval

gcc 4.6 future::wait_for() returns bool instead of future_status, this
wrapper provides forward-compatibility

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] cor::copy_* accept 1- or 2-ary actions

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] cor::copy_* returns changed count

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