show_blocks pagination

Still need to resolve "Block All" behavior and use some less generic class names, but could you advise if I'm on the right path with how pagination behaves/is presented?

- Get total count of blocks in a BlockBatch within showBlocks()
- Fetch perPage (500) blocks at a time
- Offset blocks fetch based on "?page=" querystring
- Pass currentPage and pages[] to templates/show_blocks
- pagination.mustache made for inclusion in show-blocks
- CSS counters added to style.css for numbering pagination links
- pagination.js handles detecting current page and navigating to others
- Remove 'theres_more' flag