Remove references to CEAN, it appears to be defunct

The 'download' link to CEAN has not been updated since R15B (2011!)
Add Erlang-solutions' binary packages

They are much more up-to-date than the ones included in e.g. Debian
Remove link to 'The Erlang Rationale'

The link is broken. Correspondence with the author (Robert Virding,
2014-06-17) suggested that the name is now mainly used as a conference
presentation about historical aspects of Erlang.

The interesting part in the original link was the section on
the IO system and on process groups, Jobs and JCL. This isn't
really covered anywhere else as far as I know.

As at this commit, the original document is still to be found
here: http://vidiowiki.com/media/paper/0m-V9dOL0AeY%20The_Erlang_Rationale.pdf
Update the location of the EUC proceedings

They're run by Erlang Solutions nowadays (since 2010)
Bump the current version of Erlang to 17.3
Add publication dates to books and other documentation

The idea is to help readers get an idea of which material is
fresh and which material is more historical.

Some dead material had to be removed.
Fix broken links
Remove historical cross-compilation information

Nobody needs to know how to cross-compile ancient releases from 2009
any more.
Fix broken links to the defunct trapexit.org site

Some of the material has moved to 'ErlangCentral', some
just seems gone. But ErlangCentral is a good collection
of material.