Changed loading of include files in PropertiesConfiguration.

Files to be included are now resolved using the new locate(FileLocator) method
of FileLocatorUtils (and thus the customizable FileLocationStrategy is
applied).

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1527236 13f79535-47bb-0310-9956-ffa450edef68
CatalogResolver now uses the locator-based method for locating files.

References to FileLocatorUtils.locate(FileSystem, String, String) have been
replaced by FileLocatorUtils.locate(FileLocator). This makes use of the
customizable location strategy.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1527237 13f79535-47bb-0310-9956-ffa450edef68