Process map marker JS assets through ERB

In rails 4, the assets include a digest only, so the reference to the
map markers used in the Google maps was not being properly referenced.
This commit runs the JS through ERB to retrieve the correct path to the
marker.
Merge pull request #432 from codeforamerica/map-markers-assets

Process map marker JS assets through ERB
Fixes #409 - refactors polyfills

Modernizr and polyfills were placed inside the requires module
management. However, this led to issues as (a) the polyfills are only
needed in older IE and (b) Modernizr has its own module system that had
issues with the Modernizr-Selectors plugin being loaded before
Modernizr in some instances.
Fixes #404 Adds unsupported console fix

Adds script to handle older browsers that don’t support console.log.
Fixes #433 - map marker on development

Adds `depend_on_asset` directive so that map markers images are
available in development environment.