Added the 'browser.js' asset for use by 'index.html'.
Added the 'browser.js' asset for use by 'index.html'.

This file abstracts all of the logic necessary to build the file browser
displayed in the artifacts index. It relies on 'artifacts.js' to list
and query the artifacts and builds out the UI to interact list them.

kensipe/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli