This reverts commit e3dcf0ce1f, reversing
changes made to c71e9fdf2d.
Once again we had a broken new plugin that Travis CI and local building
didn't catch.
Move existing "regtest / testnet" texts to the new subsection and link to it
Move Bitcoin Core setup instructions in devel-examples
Add a consistent introduction for devel-(guide/ref/examples)
Fix autocrossref.rb to not add links inside {% highlight %} code blocks