create GUI

[abbbe]

• listen_on: prefill with 0.0.0.0, no need for grey stuff
• merge testlog and connections tabs into one (it was the initial plan I think)
• when user clicks 'start', switch to that tab.
• the user should be able to select something in the connections treetable (we are only interested in what client sub trees are selected, don't care about selection of individual tests).
• 'report' tab should be not a tab, but a popup window. the user can invoke it by clicking 'report' button which need to be somewhere next to the treetable. form the popup the user can copy the report to the clipboard by clicking a button (like it is now).