1. A method for merging a source file directory with a destination file directory on a computer, wherein the source file directory includes a plurality of source items, the merge method comprising: for each source item included in the plurality of source items: when the source item is a file, determining whether the file conflicts with at least one file in the destination file directory, and when the file conflicts with the at least one file in the destination file directory: deleting the at least one file from the destination file directory, and moving the file from the source file directory to the destination file directory without copying the file; when the source item is a subdirectory having no corresponding subdirectory in the destination file directory: moving the subdirectory from the source file directory to the destination file directory without copying the subdirectory; when the source item is a subdirectory having a corresponding subdirectory in the destination file directory: carrying out the merge method for any source items included in the subdirectory; and when the plurality of source items are removed from the source file directory: deleting the source file directory.