Fix Paragraphs having no hight style issue

Please see a Message with multiple carriage returns and notice that paragraphs get no height.

http://beta.curriki.org/xwiki/bin/view/Messages_Group_XWikiTrainingGroup/Spacingforlines for example.

The Wiki syntax is:

line 1 (One CR)

Line 2 (two CRs)

Line 3 (Three CR) \\\\

Line 4 (Four CRs) \\\\\\

done.

The CSS at issue is:

.frame p {style.css (ligne 4988)
margin:0;
}
p {style2.css (ligne 15)
margin:0.5em 0;
padding:0;
}
p {elements.css (ligne 62)
}
html, body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, form, fieldset, input, p, blockquote, th, td {ext-all.css (ligne 9)
margin:0;
padding:0;
}

It does not have an issue in other skins-

http://beta.curriki.org/xwiki/bin/view/Messages_Group_XWikiTrainingGroup/Spacingforlines?skin=toucan

Please check impact on all editorial pages like: http://www.curriki.org/xwiki/bin/view/Main/AboutFindingCollecting http://www.curriki.org/xwiki/bin/view/Main/AboutFindingCollecting