Fix https://github.com/julianhyde/linq4j/issues/15, "Expressions.ifThenElse does not work".
Update history.
Fix https://github.com/julianhyde/linq4j/issues/8, "Javadoc generation fails under JDK 1.8".
[maven-release-plugin] prepare release linq4j-0.2
[maven-release-plugin] prepare for next development iteration
Move OptimizerVisitor to linq4j
WIP: autoconvert