use newer Ubuntu and Python in Dockerfile

handle unknown ips, e.g. from unix sockets

remove the hackish logic against replay attacks because it stopped to…

… work with new android clients

see #183

more secure defaul settings

use tls-only mode in the default config

advice to use uvloop instead of PyPy interpreter. The uvloop gives a …

…better speed and memory consumption

protect from time skewing. The proxy protocol is very sensible to clo…

…ck skew. If the skew is detected, disable advertising, making the connection directly to tg servers, instead of middle proxies

fix ipv4 resolver url

change ip address resovers since the old one doesnt work anymore

Merge branch 'master' into stable