module rewrite

I wanted to add the ability to disable the dashboard service and resolve some dependency issues and ended up with a large number of conditionals which get hard to maintain and tend to go against recommended suggestions on how to use puppet.  I have tried to keep breaking changes to a minimum.

Breaking changes I know of:
  $server => true no longer also enables the dashboard and api service.  These are now controlled by their own parameters.
  Many (all that can be?) parameters are now validated.  Shouldn't break anything, but I may have missed an option

Changes:
  All 4 sensu services are now controlled by their own config/service class
  Parameters validated
  Sensu must be installed from the main class.  Any attempt to call private classes will fail.  This allows not having to pass parameters to sub classes for consistent results.

I am running this in my environment without any issues (or changes between the old and new module), but I would like some other people to take a look at this as well.

This should resolve #123, #124,