GPII-277: Adding get/set wrapper for Android.Settings

[Android.Settings wrapper]
  * These get/set methods provides us to get/set values from Android's
native Android.Settings. This wrappers can deal with settings from
Settings.System, Settings.Secure and Settings.Global

[More changes]
  * Move current AndroidFontSettings into a separate folder called
'AndroidFontSettings'
  * Add the new code into a folder called 'AndroidSettings'
GPII-277: Add stub for the new AndroidSettings class

[changes]
  * Adding Net_gpii_AndroidSettings new stub
  * Including a line for the new classes into makestubs.sh to generate
the new stub
GPII-277: Adding Settings Handler for Android's native settings

Including settings handler as js source code into activity_manager
node module. This settings handler can deal with System, Global and
Secure settings, and this should be specified in the options block of
the payload.
It follows the current policy about Settings Handlers, this is:
  * Provide both get/set methods
  * Receives the standard payload
  * Options block aren't included in the response payload
Merge branch 'master' into GPII-277
GPII-277: Renaming nativesettings into androidSettings

* Rename module from nativesettings into androidSettings
* Moving back the java code to the original folder
* Updating ant.properties and makestubs.sh according to these changes
GPII-277: Updating platform/README.md according to latest changes
NOJIRA: Cleaning up prebuild.sh

Remove useless (and commented) source code from prebuild.sh
GPII-277: Ensure that only string value types are passed

Doing the required type conversions before calling set
GPII-277: Splitting androidSettings into its own node module

* Adding node_modules/androidSettings
* Removing the code for androidSettings from activity_manager.js
* Updating gpii.js accordingly
Merge remote-tracking branch 'javihernandez/GPII-277'