[Seaside] 2.6b1.41 compatibility

[Michel Bany]

Beware

In 2.6b1.41 (both Squeak and VW), I decided to remove three methods  
from the canvas image tag.
	fileName:mimeType:
	fileName:mimeType:document:
	data:mimeType:

So instead of coding like this

	html image fileName: 'foo.jpg' mimeType: 'image/jpg'.
or
	html image fileName: 'foo.jpg' mimeType: 'image/jpg' document:  
someByteArray.

you will have to code like that

	html image
			fileName: 'foo.jpg';
			mimeType: 'image/jpg'.
or
	html image
			fileName: 'foo.jpg';
			mimeType: 'image/jpg';
			document: someByteArray.

IMO, this is more compliant to the canvas coding style.

Feel free to reinstate the removed methods if you feel for it.

Michel.