Revert "Add keep arg to clean task"

This reverts commit 0cebfc91283ad744de8e0ca1c268147ff0274253.
Merge branch 'master' of https://github.com/sstephenson/sprockets
Fix misspelling of "algorithms"

The DigestUtils::NI_HASH_ALGORITHMS constant was misspelled as "algorihm".
Merge pull request #679 from gevans/integrity-uri-typo

Fix misspelling of "algorithms"
Extract processors_for
Merge branch 'master' into processor-cache-key