Icon class function properties make possible to render a different icon
class depending on the context of the file action.

Inline file actions had support for them already and called them passing
the file name and context of the file action as parameters. Due to this
the FileActionsMenu passes those parameters too to icon class functions
instead of just the context like done for display name functions.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>