Improve Revision History dialog to accommodate documents with title that does not fit into one line.

How to reproduce:
1. using the archetype, go to the CMS
2. edit [/cms/?path=/content/documents/myhippoproject78/news/2011/pbs-show-asserts-greenhouse-gases-atmospheric-pollutants-dimming-future] and publish the document
3. repeat step 2 for 7 times
4. check the document's revision history

actual behavior: the items in "revision history" dialog overlaps with pagination (see screenshot-1)

expected behaviour: either a scrollbar appear or the pagination is activated