Changed module interval back to default of 10 seconds. Plugin is able to handle
its proper probe interval. Smart plugin illustrates this.

Added instance name to log function. Multiple files can now be created within a
given plugin.

Added support for enabled flag to enable to allow modules to be enabled or
disabled within plugin configuration.

Added Simple plugin to illustrate using native collectd type (e.g. GAUGE).

Smart plugin:

  * Added support for variable interval polling (300 seconds)
  * Added instances to record worst and threshold values