[3.1.1] Round up imagecrash support with HTML.MaxImgLength

- Add $max to AttrDef/HTML/Pixels.php
- Add %HTML.MaxImgLength
- CSS width/height allows percents when MaxImgLength is disabled


git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1762 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/ConfigSchema/schema/HTML.MaxImgLength.txt

@@ -0,0 +1,13 @@
+HTML.MaxImgLength
+TYPE: int/null
+DEFAULT: 1200
+VERSION: 3.1.1
+--DESCRIPTION--
+<p>
+ This directive controls the maximum number of pixels in the width and
+ height attributes in <code>img</code> tags. This is
+ in place to prevent imagecrash attacks, disable with null at your own risk.
+ This directive is similar to %CSS.MaxImgLength, and both should be
+ concurrently edited, although there are
+ subtle differences in the input format (the HTML max is an integer).
+</p>