docs/man: Auto-generate markdown manpages

This patch adds auto-generation of markdown manpages, for ease of
reference in other documents and links.

docs/man/mda-lmtp.1.md

@@ -0,0 +1,62 @@
+# NAME
+
+mda-lmtp - MDA that uses LMTP to do the mail delivery
+
+# SYNOPSIS
+
+mda-lmtp
+\[**-addr\_network** _net_\]
+**-addr** _addr_
+**-d** _recipient_
+**-f** _from_
+
+# DESCRIPTION
+
+mda-lmtp is a very basic MDA that uses LMTP to do the mail delivery.
+
+It takes command line arguments similar to maildrop or procmail, reads an
+email via standard input, and sends it over the given LMTP server.  Supports
+connecting to LMTP servers over UNIX sockets and TCP.
+
+It can be used when your mail server does not support LMTP directly.
+
+# EXAMPLE
+
+**mda-lmtp** _--addr=localhost:1234_ _-f juan@casa_ _-d jose_ < email
+
+# OPTIONS
+
+- **-addr** _address_
+
+    LMTP server address to connect to.
+
+- **-addr\_network** _network_
+
+    Network of the LMTP address (e.g. _unix_ or _tcp_). If not present, it will
+    be autodetected from the address itself.
+
+- **-d** _recipient_
+
+    Recipient.
+
+- **-f** _from_
+
+    Whom the message is from.
+
+# RETURN VALUES
+
+- **0**
+
+    success
+
+- **75**
+
+    temporary failure
+
+- _other_
+
+    permanent failures (usually indicate misconfiguration)
+
+# SEE ALSO
+
+[chasquid(1)](chasquid.1.md)