always clear player before adding a new one
always clear player before adding a new one

fixes https://github.com/brion/ogv.js/issues/271

xzf158/ogv.js,paladox/ogv.js,chrislearn/ogv.js,chrislearn/ogv.js,chrislearn/ogv.js,xzf158/ogv.js,paladox/ogv.js,xzf158/ogv.js,xzf158/ogv.js,chrislearn/ogv.js,xzf158/ogv.js,chrislearn/ogv.js,paladox/ogv.js,paladox/ogv.js,paladox/ogv.js