Fix name of CGI section
Document "for" option ordering details
if-option does not exist, only if-opt
Document ini = :section syntax for ini files
Document filename:section syntax for YAML and JSON
Document the if-opt option
Remove links to non-existant quickstarts
Document the strict option
Document the set-placeholder and set-ph options
Improve uppercase magic variables documentation

This adds the minimum required version (assuming the next release is
1.9.18) and makes it a bit more explicit what file they actually refers
to.
Merge pull request #95 from matthijskooijman/master

Various documentation improvements