Changes to mod_heart* docs upon review by rjung

    <note type="warning">

        To use <module>mod_heartbeat</module>,

        <module>mod_status</module> and <module>mod_watchdog</module>

        must be either a static modules or, if a dynamic module, it must

        must be either a static modules or, if a dynamic module, must

        be loaded before <module>mod_heartbeat</module>.

    </note>

</section>

<section id="miscellaneous">

<title>Miscellaneous</title>

<p>The interval of 1 seconds is controlled by the HEARTBEAT_INTERVAL

compile time define.  This is not currently tunable at run time. To make

this module send the status packet more often, you must add to the

CFLAGS used to compile the module to include:</p>

<example>-DHEARTBEAT_INTERVAL=3</example>

<p>Would cause the broadcasts to be sent every 3 seconds.</p>

</section>    

<directivesynopsis>

<name>HeartbeatAddress</name>

<description>Multicast address for heartbeat packets</description>

    <p>The <directive>HeartbeatListen</directive> directive specifies the

    multicast address on which the server will listen for status information from 

    <module>mod_heartbeat</module>-enabled servers.  This

    address will usually corrspond to a configured  <directive

    address will usually correspond to a configured  <directive

    module="mod_heartbeat">HeartbeatAddress</directive> on an origin server.

    </p>