Allow Interval per File block for tail plugin

The allows each <File> block in the tail plugin config to specify
its own Interval value. If ommitted, will use the default.
Fix tcp state names to be like others.
AIX doesn't have MSG_DONTWAIT, define as MSG_NONBLOCK
write_riemann: send notification message to riemann via description field
Merge pull request #575 from amiron/riemann_notification_message

write_riemann: send notification message
Merge pull request #446 from bugsduggan/feature/tail_plugin_interval_per_file

Allow Interval per File block for tail plugin
Merge pull request #546 from manuelluis/mlsr/tcpconns-aix

Fix tcp state names in AIX to be like others.
Merge pull request #569 from manuelluis/mlsr/MSG_DONTWAIT-aix

AIX doesn't have MSG_DONTWAIT, define as MSG_NONBLOCK
examples/myplugin: Updated to the current plugin API.
collection.cgi: Fixed apache data-sources.
collection.cgi: Added support for df_complex types.
collection.cgi: Use -l 0 for df_complex graphs.
write_http plugin: Remove custom string and boolean config handlers.
Fix link to memcached protocol
Submit listen_disabled_num in memcached.c

This is a counter which increments when the connection limit to
memcached is reached and a socket listen is disabled.
Remove _num suffix from listen_disabled_num collected value
added new apachelog plugin with apache rotatelog tool support

added README description

improved metric definitions count will be hit_rate, and added hit_x_interval metric