-Add comparison operators to the SocketAddress class so it can be used with STL containers.

git-svn-id: http://odamex.net/svn/root/branches/net3-base@4125 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Add MessageField base class with methods for serializing/deserializing a value to a BitStream.
-Add concrete MessageField subclasses for integer types, floating point types, and strings.

git-svn-id: http://odamex.net/svn/root/branches/net3-base@4126 b0bcef46-2027-0410-bd56-ab726e9a1d04