Add openssl package descriptor and public gpg key.
Add darwin specific install for openssl 1.0.1e.
Add shared option when building openssl.
Add openssl vendor document.
Add ability for name and checksum fields for a package descriptor to
specify a scheme for the value which prevents the url field being
prefixed to the URL used for the download.

This caters for the scenario when different versions do not reside in
the same directory.
Add stub package descriptor for msmtp.
Add logic to the download command so that expected names can be resolved
correctly.

This allows for downloads from sites such as sourceforge.net where curl
would download the file with the final part of the path eg, download and
the system expects a properly formed name of the archive (as defined in
the package descriptor).
Compile and install msmtp@1.4.30 with openssl suppport.