Make WriteDepFile escape spaces and special characters

This commit makes deptools.WriteDepFile() escape spaces and the
following set of special characters in the dependencies it
writes to files used as Ninja depfiles: \, #, *, [, |.  Without this
change, dependencies with paths including any of the above may not
function as intended.

Change-Id: I3560a34de930932422200985fb479515a21d9508