一个java文件迭代器库规模

Based on [org.apache.commons.io.filefilter.IOFileFilter, org.apache.commons.io.filefilter.IOFileFilter)](http://commons.apache.org/io/api-release/org/apache/commons/io/FileUtils.html#iterateFiles(java.io.File,) but it scales. Not only a list().iterator() because it tries to upload all the files descriptors to the RAM and that is bad. Dependency Google collections http://code.google.com/p/google-collections/ Apache Commons IO http://commons.apache.org/io/