FileSystemUtils.freeSpaceKb throws exception for Windows volumes with no visible files. Improve coverage by also looking for hidden files. Some tests, which are implicitly assuming a Unix-like file system, are now skipped on Windows. Created the FileCleaningTracker, basically a non-static version of the FileCleaner, which can be controlled by the user. EndianUtils - both readSwappedUnsignedInteger(...) methods could return negative numbers due to int/long casting.