fix link to formula usage instructions

Fixed minor typo in nginx.ng.config.sls

Context parameter safety fixes

Tightened up some ng requisites.

Adds NG states

Add pillar item to disable using upstart-based services

Fixes GH saltstack-formulas/nginx-formula#14.

Updates to the readme.

fixing bug with common.sls that causes it to fail

move templates to the right place

remove extraneous nrpe include (fixes #8)

Fix source module iteration

* Fixing iteration for building nginx by source with respect
  to modules
* Adding `CHANGELOG.rst` and `VERSION` per https://groups.google.com/forum/#!topic/salt-users/zHguqsk-mds

Fix a filename and pillar key issue

* Ensure `common.sls` references correct template filename
* Use `pillar.get(...)` for message_do_not_modify with default

Re-organize nginx formula files

* Re-organize according to http://docs.saltstack.com/topics/conventions/formulas.html#writing-formulas

Added the ability to build from source or package, with luajit2 and openresty

Proper dictionary lookup