Merge pull request #921 from mapbox/base-update

update base, switch to base modals
fix gpx layer names, remove underscore
Merge branch 'mb-pages' into gpx-fix
Merge pull request #924 from mapbox/gpx-fix

Gpx fix
Fix source remote tests.
Merge pull request #927 from mapbox/source-remote-test

Fix source remote tests
Merge branch 'mb-pages' into code-error