update for jdk11 build

[jodygarnett]

• [x] source 1.8
• [x] update maven shade, compiler and resources versions
• [x] update maven javadoc, fix javadoc errors (not warnings)

The project now builds all targets including: mvn install -Pbuild-uber-jar

[aaime]

Changes look good and mostly trivial. Just wondering if we should branch off a 1.5.x before applying the PR.