Tada now collects anonymous usage statistics if it's set in the config. (refs #5)

It logs the usage on info level, and shows a info about the fact on first run with a link to a wiki page on how to disable it and how to see what was sent.
Detect now adds usageStatisticsEnabled property to config (refs #5)
Tada.DialogLauncher now sends events on source of input (keyboard, expression-reference, mic) (refs #5)

DialogLauncher was refactored a bit to match this
Added Tada.Usage.ExpressionReferenceListener and Tada.Usage.PromptInputButton services that override default services and call dialog launcher that the next input will come from this source
Moved Tada.DialogLauncher to Tada.Usage.DialogLauncher namespace (refs #5)