Fix issue 61: checking Stan version: brian-lau#61

The regex to check the Stan version will be more robust if we:
   1) *match* on the first string of numerals and dots following a "v": '(?<=v)[0-9\.]+'
   2) *split* on "." and cast the chunks to integers as before

 On branch master
 Changes to be committed:
	modified:   StanModel.m

StanModel.m

@@ -927,8 +927,8 @@ function diagnose(self)
                             'pollInterval',0.005);
          p.block(0.05);
          if p.exitValue == 0
-            str = regexp(p.stdout{1},'\ ','split');
-            ver = cellfun(@str2num,regexp(str{3},'\.','split'));
+            str = regexp(p.stdout{1},'(?<=v)[0-9\.]+', 'match');
+            ver = cellfun(@str2num,regexp(str{1},'\.','split'));
          else
             fprintf('%s\n',p.stdout{:});
          end