[Feature Request] Add ticker support

[bmigunov]

So, the suggestion is to implement a ticker (running line) feature (for the cases when we would like to save some space on the i3bar). It should move an output of a given block (with enabled feature) char by char with a given direction & interval (only if output exceeds given characters limit).

Configurable options could be: ticker - toggles ticker feature ticker_delimeter - sets the delimeter which separates beginning and ending of the given output string ticker_interval - interval which does not depend on block interval ticker_chars_limit - limit of characters to be shown at once ticker_direction - right/left