New Connection & Disconnection buttons

Instead of the connection block, adds 2 buttons (Connection &
Disconnection) with the following functionality:

- At connection, connects to the available ports (does not require user
port selection)
- Allows explicit disconnection
- Checks for non explicit disconnection (cable pulled) and closes
- Several messages for user feedback (connecting, connection
established, disconnected, no ports available, …)
Merge with repo version
remove extra line
Fix controlBar button layout issue (#24)

When hiding the cloud button, other buttons were also hidden (start,
stop, resize, …).  This is now fixed.