* Improved library access for lm-sensors and implemented use in papi.
* Fixed comment formatting
* Removed explicit "None" from return of libs().
* Added two new software release versions.
We'd like to use a consistent checksum scheme everywhere so that we can:
a) incorporate archive checksums into our specs and have a
consistent hashing algorithm across all specs.
b) index mirrors with a consistent type of checksum, and not one that
is dependent on how spack packages are written.
- [x] convert existing md5, sha224, sha512, sha1 checksums to sha256