Uniform translation of profiles to unit names

The unit corresponding to a profile named $p is netctl@$p.service.
We should not drop the suffix, since $p could contain a valid unit
suffix (although .service is not allowed).
We take care of this uniformly by wrapping around systemctl.
Additionally, `systemctl list-units` does not accept an '--active'
parameter, so we fix it to be consistent with `netctl list`.
connections/vlan: fix BindsToInterfaces length calculation

${#array[@]} requires "[@]" to count the array members. Otherwise it will
return the length of the first element which will hardly ever be 1.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Proper systemd escaping

This fixes the use of all sorts of characters in profile names/interface names.
Unhardcode paths

Remove distribution-specific paths (and allow overrides).
Documentation updates
Fix termination of wpa_actiond

wpa_supplicant would not immediately terminate with an attached ctrl monitor.
0.7 release updates