Data point batch uploading and Android app improvements

This pull request includes a rewrite of the Android app for these new features:
* Continuous scanning
* Reviewing data points
* Uploading in batches

The RasberryPi PHP code has also been changed to accept batches of wifi points, and it should theoretically be compatible with the existing database from the previous version. I have a simple version running on Heroku at http://morning-wave-7971.herokuapp.com/ that doesn't actually add the points to a database, but returns the number of results that it successfully parsed. The URL can be swapped out in res/urls.xml