ENG-6041: zkport override.
Changed DDLCompiler to use the Java lang identifier rules to determine
valid classes rather than the pattern matcher because Java class names
allow various versions of underscore and currency.
Remove unnecessary inner class.
Merge pull request #1269 from VoltDB/ENG-6109-SupportUnderscoreInImportClass

Eng 6109 support underscore in import class
Add License to dummy file used to test underscores.
Merge pull request #1270 from VoltDB/FixDummyLicenseCheck

Add License to dummy file used to test underscores.
Adding error output for various conditions for ENG-6075
Merge pull request #1265 from VoltDB/ENG-6041

ENG-6041: zkport override.
Fixes according to Paul's suggestion
Merge branch 'master' of github.com:VoltDB/voltdb into ENG-3233-stringfunc