[sldev] Art and Library tarball handling

[Soft]

Right now, for automated drops I'm uploading new art and library
tarballs to go with each svn drop, and my script puts the internal
branch and revision in the name. Most of the time, these support
tarballs don't change however. Often, they're even the same across
branches.

Would it make sense to replace the branch and version with the md5 sum
for these tarballs? Obviously this would make it tough to tell which
tarball goes with which version without referring to the commit
messages or doc/asset_urls.txt in the source drops. The onus would be
on the downloader to keep track with scripts, or by making named
subdirectories to contain the tarballs. Is this a problem?