Remove grover*.jar after build

A maven-clover2-plugin creates a groover*.jar file in $java.io.tmpdir directory. This JAR is next being dynamically added as a build dependency artifact. It must be available till end of the build.

Unfortunately Maven has nothing like post-build-cleanup phase (which would be always executed at end of build). We need a workaround for this, for example:

1) Create a new Clover goal, like clover2:post-build-cleanup, which will remove this file.

2) Alternatively, find a way to add Clover groovy runtime classes to classpath, so that creation of JAR file would not be needed anymore.

As soon as this bug is fixed, a corresponding update of Bamboo Clover Plugin is necessary. See linked issue.

Solution implemented:

Instead of playing with post-build cleanup, there are two new options available in <clover-setup/> taks (Ant) and clover2:setup / clover2:instrument goals (Maven):

• skipGroverJar - if set to true it will not extract artifact at all (can be used only if there's no Groovy code in a project)
• groverJar - target location of grover.jar file (fixed name and location instead of generating temporary file name in java.io.tmpdir)