Merge pull request #9 from MTecknology/master

Rewrote last pitfall section.
apps: added PmWiki to the list

The pull request incorporates some of the suggestions from issue #10

Please, take it into account.
style corrections by MTecknology
unified recipe into one single file

Many corrections were made; suggested by MTecknology
changed apps -> recipe
fixed whitespace problem with .. ngx::
flipped allow -> deny in hiden files logging and access
Merge pull request #11 from renich/master

apps: added PmWiki to the list
Moving apps->recipes; touched up configs; added an empty php-fpm tutorial page
Update CONTRIBUTING.rst
Added building information as well as another recipe.