[CB-3442] cordova-ver.js to cordova.js
[CB-3473] update hello world
[CB-3473] updated version, unwound dev label which causes problems with upgrade script
[CB-3473] updated cordova.js
[CB-3473] updated helloworld and js
[CB-3473] updated version to 2.8.0rc1
[CB-3442] lost commit, fix for bb10
[CB-3381] Output usage info on error for all scripts

Reviewed by Bryan Higgins <bhiggins@blackberry.com>
Tested by Tracy Li <tli@blackberry.com>