Removed old debugging line.

Removed the line "(message (pwd))" left over from debugging
`elwiki-history-page'.
Simplified `elwiki-history-page'

Made use of the new `esxml-listify' function and `kvmap-bind' to
greatly simplify the esxml-generating code in `elwiki-history-page'.
Thanks to tali713 for his help with this. :)