schema: support bytes.Reader and strings.Reader in FileTime

Change-Id: Ib42a0478782f7e421e3f3125b1fc876d27d6ee68
types: add more time parsing functions

Change-Id: I35ffdd030fbdc87db4821f00fa562580e8205731
index: index file times too, and return in index.GetFileInfo.

Change-Id: I59d91f0938c725a4cbdf5ca933cdff3529e25f5f
fs: in recent, use file's EXIF time (or modtime) time instead of permanode time

Change-Id: I4ca9132967fb781192ea981d883b242a2c159b49