Fix mepo save and allow hash in components.yaml

[mathomp4]

This release has a bug fix for mepo save as found when looking into Issue #180

Also, this release allows the use of a hash: key in components.yaml a la:

ESMA_cmake:
  local: ./ESMA_cmake
  remote: ../ESMA_cmake.git
  hash: a64765f4ddc00c62b441bb08b31585cfa645756e
  develop: develop

This needs changes because git clone -b hash is not allowed. Only tags and branches (I think?) are allowed:

   -b <name>, --branch <name>
       Instead of pointing the newly created HEAD to the branch pointed to by the cloned repository's HEAD, point to <name> branch instead. In a non-bare repository,
       this is the branch that will be checked out.  --branch can also take tags and detaches the HEAD at that commit in the resulting repository.

These updates also triggered cascades into fixing mepo status and mepo compare as we touched the sanitizer code.

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This discussion was created from the release Fix mepo save and allow hash in components.yaml.