Ported EventManager blog post to docs

- Original URI: http://www.mwop.net/blog/266-Using-the-ZF2-EventManager.html
- Edited and expanded to follow current API
hotfix tutorial.dbadapter :  should be  on assigning
Fix code-blocks

- Removed :startinline: and :number-lines: directives, and replaced with
  :linenos: directive
Merge pull request #830 from samsonasik/fix/tutorial.dbadapter

hotfix tutorial.dbadapter : 'setStaticAdapter' should be 'getStaticAdapter' on getter
Merge pull request #824 from weierophinney/feature/eventmanager-tutorial

Port EventManager blog post to docs
fix external link
fix more words
Merge pull request #833 from samsonasik/fix/external.link

fix external link and surplus word
typo: needed a slash in one of the paths
Update zend.form.collections.rst
Merge pull request #834 from bickerstoff/fix/tutorial/unittesting

typo: needed a slash in one of the paths
Merge pull request #835 from Danizord/patch-3

Typo fix