NPanday ArtifactTypes should get externalized

[Henning Gross <h....@tarent.de>]

Hi!

I need to build a special type of project. Namely wsp files. I have  
created a lifecycle and an ArtifactHandler for wsp files.
Npanday will exit giving an error "unrecognized artifact type". I  
tracked it down in the sources and as far as I see it, artifact types  
have to be in dotnet-core in class ArtifactType.java
This means I have to make my own build of dotnet-core whenever there  
is a new Npanday-release to get my Artifact Type recognized.

Artifact Types should get externalized. It should be possible to add  
artifact types via an extension or plugin configuration.

Or am I missing something?