Merge pull request #24 from sul-dlss/fix-sass

Peg sprockets and sass to versions that work with sass-rails
Refactor #show_map_div to match Rails tag rendering conventions. Fixes #6
Merge pull request #25 from sul-dlss/blacklight_map_tag

Refactor #show_map_div to match Rails tag rendering conventions. Fixes #6
merged changes and minor tweak