[MASSEMBLY-665] Added warnings about platform-depdendent filesets

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1644977 13f79535-47bb-0310-9956-ffa450edef68
Fixed IT on 2.2.1

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1645001 13f79535-47bb-0310-9956-ffa450edef68
Fixed test on windows

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1645008 13f79535-47bb-0310-9956-ffa450edef68
[MEAR-176] Upgrading maven-filtering breaks IT


git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1645035 13f79535-47bb-0310-9956-ffa450edef68
Removed unused method

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1645047 13f79535-47bb-0310-9956-ffa450edef68
Null check

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1645049 13f79535-47bb-0310-9956-ffa450edef68