New class TelnetParser

Incomplete implementation of a parser for the telnet protocol. So far it
can only replace escaped IAC bytes in the passed data.
Handle single telnet command

The TelnetParser class can now handle a single telnet command.
TelnetParser now handles multiple commands

TelnetParser can now handle multiple option commands in
the passed buffer.
Telnet subnegotations without parameters

TelnetParser can now handle subnegotations without additional parameters.
Integrate TelnetParser into TelnetClient
Merge branch 'master' into wip/write-to-display