Updated documentation for new PyBossa.JS
Updated documentation for new PyBossa.JS

The tutorial has been updated using the new pre-loading task pattern and
simpler code thanks to PyBossa.JS

geotagx/geotagx-pybossa-archive,stefanhahmann/pybossa,CulturePlex/pybossa,Scifabric/pybossa,PyBossa/pybossa,proyectos-analizo-info/pybossa-analizo-info,geotagx/geotagx-pybossa-archive,harihpr/tweetclickers,harihpr/tweetclickers,CulturePlex/pybossa,CulturePlex/pybossa,geotagx/pybossa,Scifabric/pybossa,OpenNewsLabs/pybossa,OpenNewsLabs/pybossa,inteligencia-coletiva-lsd/pybossa,jean/pybossa,proyectos-analizo-info/pybossa-analizo-info,proyectos-analizo-info/pybossa-analizo-info,PyBossa/pybossa,geotagx/geotagx-pybossa-archive,geotagx/geotagx-pybossa-archive,geotagx/geotagx-pybossa-archive,jean/pybossa,inteligencia-coletiva-lsd/pybossa,stefanhahmann/pybossa,geotagx/pybossa