Build with Groovy 2.3.0.
Assume Netbeans users use the Gradle plugin.
Rationalize the Git ignore file.
Remove IntelliJ IDEA file.
Trivial amendments to teh ignore file.
Add to Git ignore file to deal with Netbeans with the Gradle plugin.
Declare 0.4 release candidate 1.
Post 'release candidate' release number change.