first take at #272, needs refactoring
clearer comments
Merge branch 'mb-pages' into layer-list-up
move things around
Bump release version on website.
don't overwrite duplicate layers
loading class for large files
close browsefile modal when getting metadata and update mapnik-om
move source mapping into sourcelayers template
Merge pull request #725 from mapbox/loadingsource

Loading source
rename
disable source changing if custom layer list
Merge branch 'mb-pages' into layer-list-up
replace invalid characters in layer list name.
adjust typography in layers panel
cleanup
add validation to layer naming
fix console.log
fix old code
Minor tweaks, word choice.