sleep on every N'th event
add hooks for after filter
Allow appname and procid to be format strings.

Handy if your Logstash agent is parsing from multiple application
sources to send to a single syslog instance.
filter to prune fields from events
corrected some rspec tests desciptions
support for fields with array values
Plugins need to have a plugin_status set

Added comment & line for plugin_status
Merge pull request #442 from timconradinc/patch-1

Plugins need to have a plugin_status set
Merge pull request #440 from piavlo/filter/prune

filter to prune fields from events
Merge pull request #438 from wotifgroup/variable-app_procid

Allow appname, procid, and msgid to be format strings.
Merge pull request #437 from logstash/filterworker-hook

add hooks for after filter
Merge pull request #433 from piavlo/feature/filter-sleep-unslept-count

sleep on every N'th event
- SINCEDB_PATH is no longer.
- note the rename
- all tests passing; docs look OK. Ship it.