* Allow startup scripts to specify java home
The startup scripts now look for java in 3 locations. The order is from
most related to druid to least, ie
${DRUID_JAVA_HOME}
${JAVA_HOME}
${PATH}
* Update fn names and clean up code
* final round of fixes
* fix spellcheck
* Startup scripts: verify Java 8 (exactly), improve port/java verification messages.
Java 11 compatibility isn't fully baked yet (users have reported various
issues on Java 11), so block startup with an error message unless Java 8
is found. Allow overriding this decision with an environment variable.
* Message adjustments.
Suneet Saldanha
Gian Merlino
Jonathan Wei