TODO
as of 2018-07-03

*) Design a better model for preferences using ContentProvider

*) Control wpa_supplicant directly using documented sockets and commands:
   this should be the preferred way of communicating with wpa_supplicant, 
   allowing a fine-graned control over the authentication process
   and giving access to asynchronous events about the connection status.
   
*) SQLite database for storing network details:
   drop the current JSON/text-file model and build a more consistent, 
   more secure way of storing data.

*) Support wpa_supplicant in AP mode to create a Wi-Fi hotspot

*) Support captive portals (e.g. "public" Wi-Fi systems or on-campus Wi-Fi):
   (needs thorough research)
