Address book better context menu
Address book better context menu

Don't allow delete of chans/subscriptions.
Fixes #82

bmng-dev/PyBitmessage,debguy0x/PyBitmessage,timothyparez/PyBitmessage,hb9kns/PyBitmessage,hb9kns/PyBitmessage,bmng-dev/PyBitmessage,debguy0x/PyBitmessage,debguy0x/PyBitmessage,timothyparez/PyBitmessage,hb9kns/PyBitmessage,torifier/PyBitmessage,torifier/PyBitmessage,timothyparez/PyBitmessage,hb9kns/PyBitmessage,debguy0x/PyBitmessage,bmng-dev/PyBitmessage,timothyparez/PyBitmessage,torifier/PyBitmessage,torifier/PyBitmessage