Computer bower dirname once
Use file? helper
Use relative_path? helper
Extract expand_relative_path for directive processor
Only allow relative requires in the same load path
base_path -> load_path
Add :load_path to input api
Only need to normalize logical path from split
Add TODO
Pass extname into normalize logical path
Fix index logical path with extra extname
Validate asset outside of load paths
Prefer accept: over content_type: option
Allow multiple accept types
Depend on falls back to accept any content type