Update Eclipse settings to make use of a custom Spring formatter
implementation. Using a custom formatter allows us to fix a couple of
issues with the version that shipped with Eclipse Mars.1 (Eclipse bugs
The custom formatter also means that it is possible to use Groovy
Eclipse despite the fact that it has formatter regressions (see
https://github.com/groovy/groovy-eclipse/issues/142).
Fixes gh-4136
Remove README files that have been since been migrated to the reference
documentation. Also updated remaining markdown files to asciidoctor to
save having a mix of different formats.
Fixed gh-503