Fixed up the lm-utils documentation. Fixes LM-52.
Include the lm-utils documentation and write a description for the outputted API documents.
<!-- ##### SECTION Title ##### -->
LmMessageHandler
<!-- ##### SECTION Short_Description ##### -->
A handler for incoming messages.
<!-- ##### SECTION Long_Description ##### -->
<para>
A handler can be registered to listen to incoming messages with lm_connection_register_message_handler(). When a message is recieved the handlers of the correct type will be called.
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### USER_FUNCTION LmHandleMessageFunction ##### -->
<para>
The actual callback function in an #LmMessageHandler. This function is called when an incoming message arrives that haven't been handled by an handler with higher priority.
</para>
@handler: an #LmMessageHandler
@connection: an #LmConnection
@message: an #LmMessage
@user_data: user data set when creating the handler
@Returns: #LM_HANDLER_RESULT_REMOVE_MESSAGE to indicate that message has been handled, otherwise #LM_HANDLER_RESULT_ALLOW_MORE_HANDLERS.
<!-- ##### FUNCTION lm_message_handler_new ##### -->
<para>
</para>
@function:
@user_data:
@notify:
@Returns:
<!-- ##### FUNCTION lm_message_handler_invalidate ##### -->
<para>
</para>
@handler:
<!-- ##### FUNCTION lm_message_handler_is_valid ##### -->
<para>
</para>
@handler:
@Returns:
<!-- ##### FUNCTION lm_message_handler_ref ##### -->
<para>
</para>
@handler:
@Returns:
<!-- ##### FUNCTION lm_message_handler_unref ##### -->
<para>
</para>
@handler: