fix json handling for localhost event cmdline tool.
Add phone description to join event
Add logging of App usage and browser history option to  experiments.
Poll browser history when browser app is opened (currently support
android browser, chrome, and firefox). Record urls for each browser
session on browser exit.
Poll app usage and record new app usage as a paco event.
Cosmetic clean ups
Fix problem with scoping of functions in return object of js library
Create browser and app events when logging is enabled on an experiment
Add parameter and configuration about whether or not to record phone
details in an experiment's join event.
Add a list of data types collected to the experiment join flow to the
informed consent page to better inform users.
Start polling processes if necessary upon joining an experiment that
wants to poll processes.

Stop polling processes if necessary upon leaving an experiment that
wants to poll processes.
increment to latest versions of server and Android client

make executor launchable from a browser link

fix null check in cond parser

pass visual elements for conditional hiding in custom_base.js

Add experimentService in js for retrieving and saving experiment
definition.

Ad notificaitonService in js for user-created notifications.

clean up cameraService js

Change find experiments screen to say Discover

Add fields for custom notification message and source to distinguish
user notifications in js from alarm notifications.
Part 2 of notifications via js.

Logging of app usage and browser history option.

Changed EULA display to be menu-driven only not on startup.
Merge branch 'browser_app_polling' into develop
Merge branch 'develop' of https://github.com/google/paco into develop