CB-870 android: Add volume button event support

github: close #72
CB-7219 added platformVersion, removed cordova.version
CB-7219: cordova.version now outputs same value as cordova.platformVersion
CB-7219 Added back version file, added default value for compute-commit-id.js
CB-7219 made sure compute commit id is run from cordova-js repo. Set cwd to cordova-js
Merge branch 'cb-7219' of https://github.com/stevengill/cordova-js into cb-7219