Update sockets module (#301)

* Module rewrite

- WinSock version changed from 1.1 to 2.2.
- Properly check for WinSock initialization on OnAmxxAttach/Detach.
- Now natives will not be added if we can't start up WinSock.
- socket_open() is now IP version agnostic (both IPv4 and IPv6 are
supported).
- Error reporting has been changed on socket_open(), a new parameter
called _libc_errors has been added, and, if enabled, libc errors will be
returned instead of the previous made-up errors.
- socket_close() now returns a value on success/failure.
- Added non-blocking sockets at socket_open_nb().
- Added socket_is_writable() to check if a socket is ready for write.
- Added socket_is_readable() as an alias to socket_change().
- Code rewritten to be more readable, it should be self-explaining now.

* Update docs and fix AMBuild

Updated documentation following the guidelines

* Fixs for the module

- Fixed the backwards compatibility with the return codes
- Merged socket_connect and socket_connect_nb
- Added a 5th parameter to socket_open that takes bit flags to enable
the new features (libc errors & nonblocking sockets)
- Fixed an error on socket_send2 that caused the buffet not to start
from the beginning if multiple calls were made
- Updated docs
- [docs] Prefixed error codes with SOCK_
- [docs] Added the new flags SOCK_NON_BLOCKING and SOCK_LIBC_ERRORS
- [docs] Added a new stock called SOCK_ERROR_EINPROGRESS(error) to be
used when checking if a newly created nonblocking socket is connecting

* Fixes for the docs

Fix some typos, shorten lines, document SOCK_ERROR_EINPROGRESS

* Document magic numbers

No more magic

* Revert "Document magic numbers"

This reverts commit 0f233292063400ea7fdbcd5e5d5cd6e54f8cd71c.

* More docs fixes

* Fix broken socket_send2()

* Add error checking in send2()

* Remove stock

It should not be needed because nb sockets should always be checked or
writability

* Fix some identations

* Fix return codes doc

* Fix socket_recv() regression

strncopy will stop on a null byte, that makes the function unusable to
receive binary data

* More docs typo fixes

modules/sockets/moduleconfig.h

@@ -19,9 +19,9 @@
 // Module info
 #define MODULE_NAME "Sockets"
 #define MODULE_VERSION AMXX_VERSION
-#define MODULE_AUTHOR "HLSW Dev Team"
-#define MODULE_URL "http://www.hlsw.net/"
-#define MODULE_LOGTAG "SOCKET"
+#define MODULE_AUTHOR "AMX Mod X Dev Team"
+#define MODULE_URL "http://www.amxmodx.org"
+#define MODULE_LOGTAG "SOCKETS"
 #define MODULE_LIBRARY "sockets"
 #define MODULE_LIBCLASS ""
 // If you want the module not to be reloaded on mapchange, remove / comment out the next line