(3.5 port) Removed DnsEnpoint support

Removed DnsEndpoint support for addresseing. This is probably not that
important at this stage. Addresses can always be defined as plain IP
addresses and if needed the feature can be added later.
(3.5 port) Crypto class disposal method change

Changed most of the crypto class disposals from Dispose() to Clear(). This
is with the exception of RandomNumberGenerator class which doesn't seem to
have and clean-up methods in 3.5.
(3.5 port) Replace Stopwach 'Restart' with 'reset'

Stopwach.Reset() sounded like the same function. This might break.