* 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
mercurial and monotone, but slightly harder till impossible to
do properly for git and svn. Please review and eventually adapt
the code to make it work better (partially fixes issue 450)
* Monotone.php (IDF_Scm_Monotone_Stdio): add support for multiple, equally named options
* Source.php, commit.html: split-off the global commit template (which had some separate code already for SVN) and adapt the left blocks for mtn to shorten branch and tag names just like we do everywhere else
