GPII-716: PCP's method for interaction with FM via WebSockets should be more declarative

Link to JIRA: http://issues.gpii.net/browse/GPII-716

This pull request is strictly connected with Websockets communication from PCP to FM (http://issues.gpii.net/browse/GPII-539) and is not related to the pilots.

The changes this pull request brings are:
 - "Save" button in PCP applies the changed settings directly to the system by using websockets. It doesn't use the logout+login mechanism (to eliminate the chance of unexpected issues),
 - "Save" doesn't save to the prefs server.

Once this pull request is in, there will be three more (short ones) for:
 - Making this change happen instantly after a change in the model, rather than by pressing Save,
 - Making the save button save to prefs server,
 - Making the "full editor" link forfeit the logout+login mechanism as well and start functioning as the save button + switching to PMT.
@jobara, no, not exactly. When "apply settings" is invoked, first there is a check if socket is connected - if it's not, "onConnectRequest" is fired and inside the "gpii.pcp.connectSocket" method "onEmitRequest" is fired once the connection is actually achieved https://github.com/radmanovi4/prefsEditors/blob/gpii-716/src/pcp/js/socket.js#L66