Added finals to method params
There seems to be an upstream issue with the java plugin, but setting the interval to non-zero will give plugin_clone_value_list a value to use instead of interrogating the plugin_ctx struct, which the java plugin seems to have an issue with.
Added better interval dectection, and updated some log statements.

Eventually I'd like to keep a histogram of the run durations, and auto-tune the queue and pool size to minimize lag.
Merge pull request #4 from bvarner/issue_3

Calculate an interval, and include it in the ValueLists.