isReachable/isPaired as properties, correct icon

[nicklan]

This change switches is_reachable and is_paired to fetch the properties instead of trying to call a method. (not sure if/when this changed in the dbus interface, but that's how they are presented for me)

This fixes issue #31 and (I think) #38

This also switches the icon code to use the statusIconName as that seems to have the correct value. Also, in DeviceIndicator, no longer append "-symbolic" as (at least on my system) the icons don't seem to have that in their names.

(If you'd like these separated, let me know)

[Natsumi-sama]

Thanks! this fixed it for me

[mariogrip]

+1 fixed my issues

[hashar]

As I understand it, indicator-kdeconnect is now being maintained on the fork https://github.com/Bajoja/indicator-kdeconnect

Please consider installing that version instead and check whether your pull request still apply and if does submit it there?