RosBE: update svn to 1.7 or higher

Recently I've updated the GUI TortoiseSVN client that was asking me to convert the entire repository to the new SVN version. The new converted repository is not compatible with the existing rosbe svn embedded tool. I think that as people will download more of the new version it's good to prevent such problems by upgrading rosbe.

The general message for old svn clients:
svn: The path '.' appears to be part of a Subversion 1.7 or greater
working copy rooted at 'Z:\path'.
Please upgrade your Subversion client to use this working copy.