libkbfs: Add parseTlfHandleLoose, document and sharpen tlf name parsing
libkbfs: Add parseTlfHandleLoose, document and sharpen tlf name parsing

keybase/client,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client