Started on issue 544, extended commit details

* Scm.php: new SCM method "getChanges" which returns all available
  change information grouped by type
* Monotone.php: implement getChanges via get_revision
* <other scms>: rename "changes" member for getCommit to "diff" which
  matches better
* Source.php: query the commit's changes and set them in the template
* commit.html: render the changes, type-by-type. Link to the tree or
  the individual diff if applicable
* styles.css: some initial style sheet work

src/IDF/Scm/Svn.php

@@ -414,7 +414,7 @@ class IDF_Scm_Svn extends IDF_Scm
         $res['date'] = gmdate('Y-m-d H:i:s', strtotime((string) $xml->logentry->date));
         $res['title'] = (string) $xml->logentry->msg;
         $res['commit'] = (string) $xml->logentry['revision'];
-        $res['changes'] = ($getdiff) ? $this->getDiff($commit) : '';
+        $res['diff'] = ($getdiff) ? $this->getDiff($commit) : '';
         $res['tree'] = '';
         $res['branch'] = '';
         return (object) $res;