[TYPO3-core] RFC #11684: Add support for flash messages in the backend

[Xavier Perseguers]

Hi Ingo,

>> For the ExtJs part that has been requested by Xavier, Rupert, and
>> Steffen: As I'm not familiar with ExtJs and its best practices I kindly
>> ask you to contribute a solution to access the flash messages.
> 
> Steffen, Xavier, Rupert - any feedback?

Important: Please make popFlashMessages() a public method too as there are cases that need to render them differently than with your renderFlashMessages() method when using ExtJS. Just make the 
pendant of the "push" public too.

In addition, please fix typos in method comments:

- pushFlashMessage: Add*s* a flash message
- getFlashMessagesFromSession: Returns... from the se*ss*ion...
- renderFlashMessages: missing dot at the end of the description
- sometimes you put a dot at the end of a @param or @return statement, sometimes not

Besides these points, use of Flash messages will be possible with ExtJS-based backend modules (I tested it).

Regards

-- 
Xavier Perseguers
http://xavier.perseguers.ch/en

One contribution a day keeps the fork away