function checks if horace mex files are compiled correctly and return their SVN min and max version and the latest date these files were compiled If some mex files are can not be launched,the function returns the number of erros as n_errors and empty mex-files versions and dates if varargin is present, the function also returns min and max svn versions of the mex files $Revision: 626 $ $Date: 2012-05-10 18:23:53 +0100 (Thu, 10 May 2012) $