Don’t depend on target encoding in PacketBuffer#getString()

In very special cases Java might calculate a different byte size for
the resulting string depending on the contents of the byte array. This
may result in `IllegalArgumentException `s here.

Closes koraktor/steam-condenser#239
Correctly handle graceful connection end

This prevents errors when using RCON e.g. during a map change.

See koraktor/steam-condenser#239
Simplified socket error handling
Fix for how to use Maven example
Merge branch 'gcoelho-fixForMavenExample' into 1.3-stable
Add Gitter integration to .travis.yml
Finally fix encoding problems in PacketBugger#getString()
Treat player IDs as unsigned integers
Disable doclint on JDK 8
Version bump to 1.3.8
Merge branch '1.3-stable'