Bandwidth Reduction for Mobile Clients through a "Mobile Mode"

Currently, despite some attempts to fix it, toxcore still uses way too much bw and connections to be a viable im solution on mobile clients. This is not an Antox-only issue, it is an issue with any mobile client, be it on Android or iOS. Even desktop users with really low data caps would benefit from a solution.

Therefore, I propose creating a mode in which toxcore works in a reduced manner and uses much less bandwidth. This mode you could call "Mobile Mode" or "Reduced Mode", …

What would be needed for a fix: A mode in which toxcore

• maintains only one tcp connection and no udp connections at all,
• does no relaying of traffic for others, including gc (I think current tcp-only mode already does that),
• does not participate in the dht, and
• sends pings or keepalives at most every ten minutes (concrete best number to be found it).

The solution could make use of current tcp relays, which should become the standard mode of operation for "full participation mode" toxcore.

This would drastically reduce ressource consumption, and totally do without gcm or even an alternative centralized push server set up by Tox Foundation.