Removed explanations from tray menu

Removed "Change status to:" explanation from tray menu. Rationale for it is this: menu item is meant to provide a clickable action, not an explanations. Besides it already is pretty intuitive what these buttons do, no other instant messenger does such thing. I think it is bad design decision to put out-of-place explanations everywhere to accommodate users that use instant messenger for the first time, especially since function of these menu items is picked up fast and explanation is no longer needed. Not like anyone would forget what this menu does. And lastly it makes look menu a bit better by making it not as wide.

Before:
![1](https://cloud.githubusercontent.com/assets/7602544/5493710/fcd3f6ee-86f5-11e4-8079-bf060e7b9b1f.png)
After:
![2](https://cloud.githubusercontent.com/assets/7602544/5493711/ff93ea88-86f5-11e4-8912-7fbe378cea92.png)

P.S. moved connect() call to make code more consistent. Now defining all actions goes like create action -> set icon -> connect signal.