Use Docker volumes as cache in the builds

[pedroamador]

Improvements for buildApk.sh:

• Change build folder to the 'pwd'
• Add parameter: 'project" (from 'codename' project of jpl)
• Use docker volumes for ".gradle" and ".gem" folders within the build folder

@madoos this will improve performance powering up APK builds

[pedroamador]

Remove the "change permissions" final command of buildApk.sh