Update timehelper docs.

Show examples using Intl instead of date() compatible formatting
strings, as this is how the helper works.

Refs cakephp/cakephp#5127
Add bin folder to directory example in bookmarker tutorial
Update blog tutorial directory example
[fr] Update directory examples in tutorials
Correct www_root to wwwRoot
Merge pull request #1983 from cakephp/time-docs

Update timehelper docs.
build warning
[fr] wwwRoot + #1983