Changelog for network-simple-tls-0.2.1

Version 0.2.1

Ensure that the Socket TLS backend always receive the expected number of bytes. This issue showed up as the following exception previously:
```
Error_Packet "partial packet: expecting 100 bytes, got: 6"
```

Re-export Socket, SockAddr, HostName and ServiceName from Network.Socket at Network.Simple.TCP.TLS.
Re-export Context from Network.TLS at Network.Simple.TCP.TLS.
Generalize the IO monad by using MonadIO and MonadCatch (from the exceptions library).
Added makeClientContext, makeServerContext and useTlsThenClose.
Use Socket as a TLS backend instead of Handle.
Drop dependency on monad-random-api in favour of monad-random.
Dependency bumps.