Proposal: Updated layout for ask host popup box

[kgrz]

I've fiddled with the ask host popup. The changes are:

Change the form to have three items: Server IP field, port field for
events and another port field for commands. We've simplified this way
since one server has only a single IP. This keeps the form clean.

Other changes:
 * Change font to Lucida Grande. We use Lucida Grande for other items.
   It makes sense to extend that to everything else.
 * Change button text from "Ok" to "Connect".

The changes can be previewed in https://github.com/code-mancers/rbkit-client/tree/update-askhost-ui branch

[emilsoman]

:+1: for this. Btw, I think this will change when we implement #184 . I guess we'll have 2 options in the future : "Websocket" and "ZMQ".