More specs

Hi @miketheman ,
As it's a part of the roadmap I've tried to add a lot of specs. I still need to do all the modules and the source recipe, but I think it's a pretty good start. I'll add more as soon as I have some time.

Let me know what you think!

Cheers

example : 
```
nginx::commons
  common recipes
    includes the common directories
    includes the common scripts
    includes the common configuration
  common configurations
    configures nginx
    marks nginx to be reloaded when changing nginx.con
    configures the default nginx site
    marks nginx to be reloaded when changing the default site
    enables default site
    When the default website is disabled
      disables default site
  common directories
    creates nginx dir
    creates nginx log dir
    creates nginx pid dir
    creates nginx available dir
    creates nginx enabled dir
    creates nginx conf.d dir
  common scripts
    creates nxensite script
    creates nxdissite script

nginx::default
  includes the nginx recipe for the desired install method
  starts the nginx service
  includes all the default modules recipes

nginx::ohai_plugin
  create nginx ohai configuration
  reloads ohai
  includes the ohai default recipe

nginx::package
  includes the ohai plugin
  installs nginx package
  enables the nginx service
  includes the nginx common recipe
  not configured to use Nginx/Epel repo
    doesn't includes the Nginx or Epel repo recipe
  Debian platform family
    configured to use Nginx repo
      includes the Nginx repo recipe
  Red Hat platform family
    configured to use Nginx repo
      includes the Nginx repo recipe
      configures package resource to exclude default repo and install it
    configured to use Epel repo
      includes the yum-epel recipe

nginx::repo
  Debian
    includes apt recipe
    adds apt repository
  Rhel
    adds yum repository
  Fedora
    adds yum repository

Finished in 9.13 seconds (files took 3.13 seconds to load)
36 examples, 0 failures

ChefSpec Coverage report generated...

  Total Resources:   19
  Touched Resources: 16
  Touch Coverage:    84.21%
```