Rename "anything" to "helm"

According to http://www.emacswiki.org/Anything, "Anything" has been
renamed to "Helm" and apparently all the symbols have changed
accordingly.  This commit fixes the names; it loads without error and
at least git-show appears to function correctly.
Merge pull request #1 from liamh/master

Rename of "Anything" to "Helm"