Moved misplaced constants to AssetResolverInterface
Added AssetResolverInterface and implementation
Factorized asset manipulations in SmartyAssetResolver
Added AssetResolver implementation
Passed the AssetResolver to the constructor
Hooks are now using the AssetResolver.
Moved asset resolution code into SmartyAssetResolver
Fixed comments, added debug messages
Fixed comments, directory separator usage, clarified code.
Fixed code style
Fixed tests
Removed the blank line which disturbed Scrutinizer
Changed ' to " to enclose attribute values in generated HTML
Fixed unit tests
Merge pull request #755 from roadster31/assets-fix

Assets management improvements