Issue #283 - Overhaul preferences layout

Fix preferences layout in order to avoid a text above a checkbox. Give
some padding to the screen to increase the readability.
Issue #283 - Fix scrolling bug in Settings screen

Some texts were leaving a trace while scrolling the list. Now the scroll
is smooth. Give some padding to the screen as well, to increase the
readability of the content.
Issue #290 - Display just-synchronised surveys in the home screen

After downloading and synchronising all the surveys, the home screen
menu is now automatically refreshed, sending a broadcast intent that
will be received in the home screen, invalidating the previous data.
Merge branch 'develop' into feature/surveyreload
Merge branch 'master' into develop
Fix FLOWrest-adapter check for existence of meta message object
Merge branch 'develop' into feature/appui
Merge branch 'develop' into feature/surveyreload
[#288] Replaced use of file.separator system property with a simple '/' in the InstanceConfigurator class.
Merge branch 'master' of github.com:akvo/akvo-flow into develop
Issue #298 - Set the imei property when saving a DeviceSurveyJobQueue

* The imei property needs to be defined for a property lookup
Issue #300 - Convert EOL char to unix

* It's just EOL change, no other code change has been introduced
Issue #300 - Remove trailing white space
Issue #300 - Generate GWT code only for WebKit browsers
Issue #303 - Check the MD5 checksum to ensure a successful upload to S3

* Generate a MD5 checksum for each file uploaded to Amazon S3, to be
compared with the one returned in the etag.
* Parse HTTP response to extract the etag located in 'Location' header.
* Close HttpURLConnection to release its resources.
* Clean up - use List interface for declarations instead of ArrayList implementation.
Issue #310 - Secure calls to testharness servlet

* The calls to /webapp/testharness are now secured and
  the user requires `SUPER_ADMIN` role
Issue #305 - Implement duplicated QAS removal

* Adds a way to remove the duplicated QAS entities `questionID -
  surveyInstanceId` using the testharness
* It uses the configured backend for processing
Issue #305 - Reimplement duplicated QAS deletion

* Use Memcache service instead of local map
* Spawn a new call if we need to process more entities
Issue #305 - Increase cache expiration to 12hrs
Merge branch 'feature/appui' into develop