Eliminate 'jungerl' references

Jungerl isn't used much anymore, most Erlang projects
are on github now
Remove trailing whitespace
Fix the simple link checker

- Be more picky in which things are treated as links
- Use " instead of ' for all URLs
modernized the GUI section
Merge branch 'modernized-gui-section' of https://github.com/massemanet/Erlang-FAQ into temp_mats

Mats updated the gui section
Fix broken syntax in a link
Update link to University of Kent (make it less specific)
Add a paragraph on Proper and Triq
Remove the reference to the shared/hybrid heap

The shared and hybrid heap options were removed entirely
in ERTS 5.9.2 (see release notes, or commit 8ca1414c)
Add three new recent books about Erlang
Update information about Erlang conferences
Remove defunct and abandoned Erlang-related sites
Update (after review) the 'academic questions section

- Remove 'What I can do for Erlang?'. That made sense a decade
  ago when open-source Erlang was new. Now, it's outgrown that
  sort of thing.

- Remove the 'flamewars' section. There aren't many on erlang-questions
  any more and most of the classic ones are closed subjects, e.g.
  the 'dialyzer' has pretty much stopped the deadlock about "there's
  no type checker so it sucks".

- Update the OO section.

- Update the description of how the GC works; important things
  have changed since the VM went SMP.
Improve reference to the German Erlang book

- Fix the title spelling
- Add a link to the publisher
Add a Spanish book about Erlang
Add the latest Erlang book: Learn You Some Erlang