Refactored states and tabs
Fixed tabs back button / history

Apparently we cannot use the same controller to show news items
for different sections.
Fix date-time on news item info page
Fix in setting android build version

Setting version seems to be quite a pain right now. Version name is set in
the config.xml. versionCode required for google play is set from the
Android manifest template in platforms.
Added gulp build & sign APK tasks
Added version info and package.json updates
Bumped Android API requirements to level 8