Big Networking Cleanup

There is still a bit more work to do in a followup CL to remove the EndpointInfo interface - there's bugs there. Also on RtcToNet to properly encapsulate each session. 

Big changes: 
* TCP connection isn't just for connections we receive: it can be used to create new connections too
* Removed NetClient, this is now just a tcp connection
* New simplified build directory layout has a typescript subdirectory for all typescript code to have a common path structure to find dependent files. 
* Uses new build-tools structure. 
* freedom files now called freedom.json
* Cleaned up/standardized use of Net.Endpoint (represents both an IP address and a port)
It tests that proxying works at all, which is arguably something we care about.