doc: modified userguide and latex2html.sh to generate html page with images...

doc: modified userguide and latex2html.sh to generate html page with images (latex2html command was substituted by tth). (This time in the trunk...)

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@3605 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534