Avoid use of non-classes elements in display pages

[dmartinc]

In events such as:
​http://indico.cern.ch/conferenceDisplay.py?confId=85747
look bad compared to the old version:
​http://indicoprev.cern.ch/conferenceDisplay.py?confId=85747

In this event, the creator probably pasted HTML into the description editor of the old version some time ago, and then kept on cloning the events. The description HTML has <h1> tags. <h1> tags are used by Indico for the meeting title, which is given a white color through common.css with a rule for all the h1 elements. In the old indico however, the CSS color for <h1> was black.

Whether this is a good way of managing a meeting or not, it would be nice if we did not use <h1> elements and similar in the display pages and instead used <span> or <div> elements with a class. This will require modifications in each of the concerned layout's XSL and CSS files, but it will avoid collisions between the Indico-generated HTML and the user-generated HTML in the description or other fields.

[dmartinc]

Some comments after discussion between the developers:
-This task is related to #3
-We should not replace <h1> by <span> with classes because <h1> elements also have semantic meaning. For example in a meeting page they are the most important element of the page.

So maybe we should keep <h1>, but giving it a class and avoid having Indico's common.css give a style to non-classed <h1> elements? :)