sc ide: improve status box context menu interaction

* open context menu on click, regardless of modifiers or mouse buttons
* align bottom of context menu with top of status box
sc ide: refactor, add context menu to interpreter status box

Separate implementations of interpreter and audio status boxes from main
window, and improve their context menus.
sc ide: audio status box - remove useless actions from context menu
sc class library: simplify and fix Volume
sc ide: ScServer - refactor, when restoring volume also unmute