Concurrent file access conflict handling

To make EasySVN as easy as possible for the users we should make EasySVN so that it handles concurrent file access and editing conflicts in the similar fashion as does the Dropbox.
The way that Dropbox handles editing conflicts is if two users share access to a file (either through sharing the same account or within a shared folder) and a conflict between their two versions appears, the Dropbox server retains only the first version to fully make it to the server. When committing a file, the dropbox client sends up an identifier which represents the last version that was successfully synced to it (i.e. the copy that is being worked off of). The server only allows the file to be committed if the identifier matches the latest version on the server. If there's a mismatch, the other machines receive a conflict and spin out local copies. The other machines will get copies of the conflicted file with a suffix like "(Drew's conflicted copy 1-1-2011)." Users can then manually fix the conflict and remove the extra copies of the conflicted file.