Adds gitignore rules
Fixes forgotten return
Adds an app to handle UDP.

This provides an API for other apps to register callbacks for a given port

Reception functional, still have to implement transmit
Changes prototype of request_packet_out

Now returns a handle to the created connection (useful in some cases)
UDP app functional

It is far from being optimal (and especially concerning buffer copying),
but it works and is completly outside of Smews core.
UDP now uses the in callback return value

This makes a better use of the connections
Adds comments
First version of dhcpclient app
commits ip configuration on ack
Fixes dhcp bug (swap ports when generating request)
DHCP now uses Client FQDN option

This allows the DHCP server to register a DNS entry with smews as client name.