restart without page reload.
set script url to https://miserlou.github.io/OpenSpritz/spritz.js?callback=cb
remove alert(); set wpm to select (0) when show_spritz()
More readable: if 'undefined' create spritz else show_spritz
More readable: if 'undefined' create spritz else show_spritz
Merge pull request #37 from smielke/master

restart without page reload.