refactored out "counter" into a plugin
CLI options and config file parser logic refactored into separate package config
Refactored Plugin interface

Breaking changes:

There are quite a few. This is probably a good start for a upcoming 1.0 branch

All CLI options changed. See the README for the full information.
- options start with two dashes now (-port 8080 --> --port 8080)
- added shorthands (-p8080)
- -elasticqueries was removed.
- The -freq flag needs a unit now. This means that you can specify minutes (or hours, ...) for the polling interval, but this also means that you have to add a s to keep the previous behaviour (now: --freq 30s)
- options can now be given via environment variables
The config file has a yaml syntax now and is more generic. Check out the README.md
The interface for custom monitors is completely overhauled. See BUILD-CUSTOM-MONITOR.md for the full information.
- a plugin can now contain multiple monitors (for multiple queries)
- global options may be passed to a plugin
- a query might consist of much more than a simple string

Enhancements

Closes #18, closes #6