server: Expose all headers and resource

Add accessor functions to protocol, and then server, that allow users to
examine ALL headers sent by the client, as well as the resource string
sent by the client. Make some darray functions take a const darray*
pointer where appropriate.
Makefile: Fix library targets
python: Add functions for resource and headers

Add accessors to ServerConn object to retrieve the resource string sent
by the client, as well as a dictionary of all headers sent by the client