Improve unicorn init scripts

* Remove unnecessary messages to stdout for restart
* Add tags to init script tasks so that they can be isolated.
Merge pull request #33 from dpla/improve-initscripts

Improve unicorn init scripts
Make Omeka log errors

Change the error-logging setting (log.errors) so that errors are
always logged.  Make this independent of debugging, such that debug
output may be on or off, but we always have errors written to the
log.
Improve NGINX worker, connections, and body size

* Parameterize NGINX worker_processes to automatically reflect the
  number of CPU cores in the system.

* Set higher worker_connections, which should be fine given the
  number of allowed open file descriptors.

* Update some comments about client_max_body_size.  Explicitly
  declare this in the Wordpress NGINX virtual host, and make it
  consistent between blocks that relate to the frontend site.

* Also increase PHP / Wordpress max. request body size, which
  affects the maximum size of a file uploaded to the Wordpress
  site.