Added auth verifying.
Another pretty big commit.

Main achievment - added support for work with database for saving users data there.
Secondary - bytr package is now fully-functional (i think so, but didn't really tested all functions). And also bytr now supports writing! Yay!
The last, but not least - sessions support. There are now persistent user objects and temporary session obj per each connection, which all reffer to one user object, that is kept in memory till at least one session exist.
When all session are finished, user object is automatically GC-ed, all changes are stored to database.
From now i don't have to care about how the fuck my data is stored - i just work with session object and it all goes to database whenever i want or whenever needed.

YAY, I'M BEST PROGRAMMER IN DA WORLD!
Fix to make user loader attemping to parse timestamp value AFTER checking if the entire fucking row was got from database.
Fixed runtime panic when tonns of clients try to connect at the same time.

I know, that mutexes is better in this situation, but as fas as login section is'nt that critical - i've done syncing with go chanells.
InitSessions should now be runned as goroutine, cause it now manages everything that happens with user objects in memory.
Server stress tests pass with 2500 clients connecting and authenticating, yay!
Bytr package refactored a bit. Now using binary package everywhere.
Also added ReadX() method for reading custom data through binary.
Some comments translated to english.
Buffering added for connections chan.
If database is unavailable, app immediatly stops now.
Fixed signed bytes reading/writing in bytr package.