SSID containing ampersand & can't be set

[brahma-dev]

As discussed in this thread
https://community.particle.io/t/photon-cant-connect-to-ssid-with/43446

Android app does not correctly set the WiFi credentials when containing certain characters (e.g. ampersand &).
Setting the credentials via CLI works just fine, but when set via Android App the device just can't connect.

Copied from particle-iot/android-app#20