Document TimeHelper::nice takes $format as param

As per the [TimeHelper::nice source code](https://github.com/cakephp/cakephp/blob/master/lib/Cake/Utility/CakeTime.php#L349), it can take $format as param. 

So Document that in the book.
begin translating "TimeHelper"
[fr] [ja] Follow f0f1ded

Update links to point at the head of the repo.
Update html.rst

type under scriptblock. Changed $this->html to $this->Html
Merge pull request #576 from terpfear/patch-1

Update html.rst
[fr] [ja] Follow 94d64e978a4e77c7987ac4aac038c491520a144e

Update html.rst
finish translation 'Time helper' in Japanese
Merge pull request #577 from yuxxxx/ja-time-helper

Translation 'time helper' in Japanese
Merge pull request #416 from gaurish/master

Document TimeHelper::nice takes $format as param
[fr] Follow #416

Document TimeHelper::nice takes $format as param
Updates docs for CakeTime::format().
Merge pull request #579 from Phally/caketime-format

Updates docs for CakeTime::format().
[fr] Follow #579 and add missing in parts in time.rst
Fixed parameter name
Merge pull request #580 from aparticka/patch-1

Fixed parameter name
Provided another example when the $route supplied uses default routing

Invalid argument supplied for foreach() in [.../lib/Cake/Routing/Route/CakeRoute.php, line 380]
Merge pull request #581 from jbrusich/patch-3

Provided another example when the $route supplied uses default routing
Improved URL Rewrite settings in web.config to also catch favicon.ico
Merge pull request #582 from ravage84/favicon

Improved URL Rewrite settings in web.config to also catch favicon.ico
[fr] Follow #580 and add missing parts in form helper