Allow to pass scalac option in command line

[fanf]

Sometimes, we want to test ad-hoc scalac options, for example to debug a scalac crash.

For now, we have to edit the pom to add them in ..., what is not really user friendly when you don't know exactly what option you are really looking for, and have to test a dozen -Y ones.

[davidB]

The request is about additionnals parameters (not a replacement).
Are you ok with something like http://alchim31.free.fr/mvnsites/maven-scala-plugin/run-mojo.html#addArgs ?

[fanf]

It would be perfect !