Extended properties for file-based builders by FileLocationStrategy property.

The FileLocationStrategy to be used for resolving the file to be loaded can now
be specified in the builder's parameters object.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1527242 13f79535-47bb-0310-9956-ffa450edef68
Removed access to default file system in test case.

In future, the file system will have to be set explicitly if another one than
the DefaultFileSystem is to be used. Adapted the test class correspondingly.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1527243 13f79535-47bb-0310-9956-ffa450edef68