Take ErlyDTL from the official (maintained) repo.

Hi,

I know it's been a long time since you touched this project, but erldocs.com is a very handy piece of work and I would like to later push my compiled docs of the latest Erlang/OTP builds.

So this PR fixes ErlyDTL's compile error on Erlang ≥R13B04. Now erldocs builds without issues.

I am compiling the docs and will send you something via GitHub or Twitter.
Thanks for your good work.