Document how to use compiler config script in maven

[skwirking]

The new feature to enable the usage of a compiler configuration script (#127) is great.

It's documented here:
https://github.com/groovy/groovy-eclipse/wiki/Groovy-Eclipse-2.9.2-Release-Notes#support-for-compiler-configuration

But that documentation doesn't say how to configure maven to use a config script. It only shows an example for setting it on the eclipse UI.

[eric-milles]

I haven't released the necessay batch compiler artifact for Maven support. You can produce the artifact from sources if you want to test. An example POM can be found here: https://github.com/groovy/groovy-eclipse/blob/master/extras/groovy-eclipse-compiler-tests/src/it/config-script/pom.xml

[eric-milles]

Updated https://github.com/groovy/groovy-eclipse/wiki/Groovy-Eclipse-Maven-plugin