Update downloads URL

This page contains all the available downloads for Tox.
Removed unnecessary parameters
Merge branch 'olologin-master'
Merge branch 'patch-2' of https://github.com/Proplex/ProjectTox-Core
fix the memory leak in new_TCP_server function
Merge branch 'lobiCode-myChan'
Added function to check if packet sent with net_crypto was received.
Removed send withid functions from api.
Fixed gcc warnings.
Lossless crypto packets can now be sent without the congestion control applying to them.
Removed useless code.
Speeded up start of file transfers.
Add support for user avatars in the core protocol

Add a protocol and the APIs to straightforwardly support user avatars
in client applications. The protocol is designed to transfer avatars
in background, between friends only, and minimize network load by
providing a lightweight avatar notification for local cache validation.
Strict safeguards are imposed to avoid damage from non-cooperative or
malicious users and to limit network usage.

The complete documentation is available in docs/Avatars.md and sample
code is available in testing/test_avatars.c.

Code and documentation are released under the GNU GPLv3 or later, as
described in the file COPYING.