Assembly file fixes

- excluded META-INF/maven files during unpacking
- using "tomcat7.0" and "jboss-as7.0" in the <id> element
  leads to the <type> of the dependency being "0.war" instead of war.
  For example:

  <dependency>
    <groupId>org.kie</groupId>
    <artifactId>kie-wb-distribution-wars</artifactId>
    <version>6.0.0-SNAPSHOT</version>
    <classifier>tomcat7</classifier>
    <!-- !!! 0.war instead of war !!! -->
    <type>0.war</type>
  </dependency>