add default account property and commands associated with them
add a bit of default account autocomplete
finish /account default ac
add some tooltip messages for /account and /connect
/connect supports default account
removing the account connected to the default account removes the default account as well
added warning about options not being used
Added CHANGELOG
update CHANGELOG
Merge remote-tracking branch 'incertia/connect-default'

Conflicts:
	CHANGELOG
Merge branch 'master' into xep-0223