* small doc cleanups in PollEvented
* small doc cleanups in IoToken
* improve crate level documentation
- Add links to the futures, mio and tokio-uds crates.
- Add links to various structs and types mentioned.
- use eprintln for error reporting in the example.
* improvements to the UdpSocket documentation
- Fixed links usage.
- Removed references to a no longer existing `Window` struct.
- Made notes about using functions in context of a future.
* documentation improvements to UdpFramed and UdpCodec
- Since HTTP uses TCP (QUIC aside) using it as an example in an UDP
protocol feels wrong.
- Make the note of tampering with the underlying streams more explicit.
* update reactor module level documentation
Adds an explanation of every public struct.
* expand Handle and Remote documentation
* expand net module documentation
Adds an explanation of every public struct and how they work together.
* update TcpListener documentation
Reorder the various option methods; get first then set.
Note about panicing added to poll_read.
* remove mention of none-existing future R
* improve documentation of TcpStream
* fix UdpSocket doc
This when wrong when merging various commits.