Allow builds to succeed even if javadoc doclint fails

[jrha]

• Reformat pom files with xmllint in utf-8 mode for consistency.
• Disable doclint to allow builds with JDK 1.8+. In JDK 1.8+ doclint errors cause the build to fail, this restores the more tolerant behaviour.

This change requires JDK 1.8+.

[jrha]

@stdweird merge this and I'll build 1.58 :innocent:

[ned21]

In JDK 1.8+ doclint errors cause the build to fail, this restores the more tolerant behaviour.

Presumably at some point in the future this will become a hard error? Is it worth opening an issue recording which docs in what codebase need updating for easy future reference?

[jrha]

@ned21 the point in the future that it became a hard error was several years ago — the Java community reacted quite negatively (e.g. http://blog.joda.org/2014/02/turning-off-doclint-in-jdk-8-javadoc.html), from what I can see some of the "errors" are Maven tags that doclint just doesn't understand.

[jrha]

I'm going to merge this so I can build 1.58 and progress with the rest of the release, we can try other options later if need be.