docs: Document esp module for ESP8266.

I document as much as I could guess from experiments and reading the
code for the ``esp`` module for the ESP8266 port of Micropython.

For now the tag has to be set manually with -t option when building,
when we have properly split documentation, there will be a separate
config file for esp8266 with that the tag "port_esp8266" set.

To build use:

make SPHINXOPTS="-t port_esp8266" html

1 files changed, 82 insertions, 0 deletions

diff --git a/docs/library/esp.socket.rst b/docs/library/esp.socket.rst
new file mode 100644
index 000000000..4f5234a15
--- /dev/null
+++ b/docs/library/esp.socket.rst
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+class socket -- network socket
+==============================
+
+``socket`` is an object that represents a network socket. Example usage::
+
+    socket = esp.socket()
+    socket.onrecv(print)
+    socket.connect(('207.58.139.247', 80))
+    socket.send('GET /testwifi/index.html HTTP/1.0\r\n\r\n')
+
+Constructors
+------------
+
+.. class:: esp.socket()
+
+    Create and return a socket object.
+
+
+TCP Methods
+-----------
+
+.. method:: socket.connect(addr)
+
+    Connect to the adress and port specified in the ``addr`` tuple.
+
+.. method:: socket.close()
+
+    Close the connection.
+
+.. method:: socket.accept()
+
+    Accept a single connection from the connection queue.
+
+.. method:: socket.listen(backlog)
+
+    Start listening for incoming connections.
+
+    Note: Only one socket can be listening for connections at a time.
+
+.. method:: socket.bind(addr)
+
+    Bind the socket to the address and port specified by the ``addr`` tuple.
+
+.. method:: socket.send(buf)
+
+    Send the bytes from ``buf``.
+
+.. method:: socket.recv()
+
+    Receive and return bytes from the socket.
+
+
+UDP Methods
+-----------
+
+.. method:: socket.sendto(data, addr)
+
+    Placeholder for UDP support, not implemented yet.
+
+.. method:: socket.recvfrom(addr)
+
+    Placeholder for UDP support, not implemented yet.
+
+
+Callback Setter Methods
+-----------------------
+
+.. method:: onconnect(lambda)::
+
+    When connection is established, call the callback ``lambda``.
+
+.. method:: onrecv(lambda)::
+
+    When data is received, call the callback ``lambda``.
+
+.. method:: onsent(lamda)::
+
+    What data is finished sending, call the callback ``lambda``.
+
+.. method:: ondisconnect(lambda)::
+
+    Call the callback ``lambda`` when the connection is closed.