Remove params class

This isn't useful to us when we don't intend to support multiple operating
systems.
Update init.pp docs.
Manage /etc/heka config directory

This will contain all of heka's config files.
Upstart script for heka

Debian package doesn't ship with one so we have to provide our own.
Add heka::plugin defined type

For configuring heka plugins.
Correct metadata in CHANGELOG/LICENSE/Modulefile
Add heka::plugin::json_event_decoder

Install a LUA decoder for json_event entries.
Add heka::plugin::graphite

Setup `CarbonOutput` to send `statmetric` messages to Graphite.
Add heka::plugin::tcp_input

Setup `TcpInput` to receive messages from another Heka instance.
Add heka::plugin::tcp_output

Setup `TcpOutput` to send messages to another Heka instance.
Add enable param to heka::plugin::tcp_output

So that this plugin could be included on all machines and selectively
disabled on machines that are also running `tcp_input` as an aggregator.
Add heka::plugin::elasticsearch

Setup `ElasticSearchOutput` to send messages to Elasticsearch.
Add heka::plugin::dashboard

Setup `DashboardOutput`.
Mention plugins in README.
Link to heka in README.
Add note about packages in README.
Release 0.0.1
Merge pull request #1 from alphagov/new_module

New module for Heka