Create Statistics section

[liebscher]

Would like to be able to view some statistics on the collection.

• [x] Quick jump to and from the section and the top of page.
• [x] Bar graphs / counts for genres (since genres are from artists, limit to unique artists)
• [x] Histogram of release years
• [x] Histogram of runtimes
• [x] Stats on comparisons (total #, # of albums without comparisons, most controversial album (variance in scores))