* refactor posix.nim
* types move to separate files for platform-specifc and generic
("other')
* consts move to separate files that get autogenerated by detect.nim
* proc's stay where they are for now, though in a second stage might
move as well
* fix missing when
This change was done to avoid confusion with TCP/IP raw sockets. Native sockets
module represents handling native system low level socket API in general and is
not just limited anyhow to TCP/IP raw sockets.
A stub lib/deprecated/pure/rawsockets.nim module has been added as
compatibility layer for old code using rawsockets, so this change will not
break existing code.
