#36 TDirectorySync: HandleHidden property to skip hidden and system entries

[Thomas Mueller]

Since [bugs:#74] (r2458) TDirectorySync.CheckOneWay and TDirectorySync.SyncOneWay always include hidden and system files and directories, as they did before r2051. That is the right default for a sync, but a consumer cannot opt out: a sync also copies desktop.ini, Thumbs.db and the like, and with a drive root as the source it also handles System Volume Information and $RECYCLE.BIN (not measured; without admin rights the former cannot be listed, so probably an empty directory of that name is created in the destination).

Proposal: a HandleHidden: Boolean property on TDirectorySync, default True, passed to the two TSimpleDirEnumerator.Create(SrcDirBs + '*.*', ALL_FILES_ATTRIB_SET, True) calls in place of the True. Plus a test in FileUtilsTest that a sync with HandleHidden = False leaves out a hidden file and a hidden subdirectory.

Found by a code review. No consumer in the checkout needs it yet, TDirectorySync is only used by the tests.