initial framework for asset dependencies
added AssetInterface::getSourceContent()
added CssUtils
moved patterns to constants
added CssUtils::extractImports()
initial pass at making SassFilter dependency aware
refactored CacheBustingWorker to use deep mime
made some members protected
minor test fixes
cleaned up use statements
fixed typo
cs fixes
added AssetManager::clear()
renamed PathUtils as VarUtils
moved getCombinations to VarUtils
updated SassFilter::getChildren() for partials
fixed tests