Add require_tree support in compiler
Add require_tree support in processors
Use a separate file for sprockets’ require_tree
Add require_tree support to builder
Test require_tree support in Opal::Environment
Switch to maccman/sourcemap (WIP)
Update the stdlib version of sourcemaps
Code layout
Fix the Ruby mime type
Just put the last line for a plain js
Fix Ruby source map mappings generation

1. The code passed should have been the original code, but we only have access to the generated code

2. The order was wrong, first it needs the generated offset and then the source one
Update spectator mspec config
Workaround the empty sourcemap bug

See https://github.com/maccman/sourcemap/issues/11
Avoid mutable strings

See also: https://github.com/maccman/sourcemap/pull/12
Update sourcemap gem
Backport maccman/sourcemap#13
Merge pull request #584 from opal/source-maps

Source maps 🌐🌍