[Typo3-dev] Crop on HTML contents: new htmlcrop extension

[Davide Principi]

I published a new version of the previous user class. I registered it as 
"htmlcrop" extension. Even if it's not a true extension, I think in this 
way it should be easier for you to check it out and test.

It's very simple, and now I think it _doesn't work with HTML comments_. 
I have to test another regexp pattern to match comments, also...

Anyway I've done all tests with config.disablePrefixComment = 1

If you think this is good we can add it to the existing crop function.
A similar function may bring a benefit to other plugins such as 
teasers", or "content-includers".

Davide Principi