* HashFromNode returns a deterministic cryptographic digest for a directory tree
* VerifyDepTree verifies dep tree according to expected digests

* prevents many accidental hash collisions

* trying to figure out condition of the testdata_digest directory on the build box

…ToSlash()

* some more edge test cases added

Remove any CRLF sequences in buf, using `bytes.Index` because that
takes advantage of machine opcodes that search for byte patterns on
many architectures. This operation is done in two parts: find and
record the CRLF sequence positions, then loop through and copy bytes
to eliminate the CR bytes.

* Only works with directories; no longer with files.

* Takes a single argument, that of the directory to hash.

* Hashes existance and type of all file system nodes in the directory
  that it finds.

* When hashing file system node names, it no longer includes the
  prefix matching the directory name parameter.

* In line with the original document describing hungarian notation,
  all file system path variable names have been prefixed with either
  `slash` or `os` to differentiate whether the variable holds a slash
  delimited pathname or a pathname delimited by an os-specific
  pathname delimiter. This is to make it much easier to visually see
  whether we are using the wrong pathname "type" than desired.

* device files, named pipes, sockets found in a vendor root tree are
  also reported, and will result in a status of `NotInLock`, because
  those node types are generally not in source control.

…ot match want status

* thanks megacheck :)