Log Message:
Update meld to 3.15.0:

2015-10-05 meld 3.15.0
======================

  Features:

   * New API for version control plugins with more consistent interfaces and
     data structures across different plugins, enabling many minor
     improvements (Kai Willadsen)
     * Support the conflict resolution prompt in file comparisons for all VCs
     * Improve caching behaviour for some version control plugins
     * Better sensitivity handling for version control actions
     * Cache and show more metadata (e.g., file renames)
     * Several version control plugins have not been ported to the new API; the
       current list of support plugins is: Git, Mercurial, Subversion 1.7+,
       Bazaar
   * Faster rendering in file comparison view, enabled by new GtkTextView API
     (Kai Willadsen)
   * Move to using GtkSourceView style schemes with Meld-specific colour tags
     for highlight colours; this lets themes include colours that match the
     sourceview theme (Kai Willadsen)
   * Offer to open binary files externally (Pratik Dayama)
   * Show the common ancestor in conflicting regions (and the merged file
     everywhere else) when viewing conflicts through Meld's version control
     view; currently this is only supported under Git (Kai Willadsen)
   * Support showing staged/partially staged status of files under Git (Kai
     Willadsen)
   * Update preferences dialog to new style with headerbar (Kai Willadsen)

  Fixes:

   * Documentation updates (Andrew Beyer)
   * Fix crash with some GTK+ versions when using --output (Kai Willadsen)
   * Fix merge-all action not working at all (Kai Willadsen)
   * Fix creating patches with unicode path names (Kai Willadsen)
   * Fix copy-to-clipboard option in patch dialog (Kai Willadsen)
   * Fix diffmap alignment for new GTK+ allocation behaviour (Kai Willadsen)
   * Improve float accuracy in folder comparison timestamp resolution (Kai
     Willadsen)
   * Fix default SVN keyword filter to escape $ characters (Kai Willadsen)
   * Fix display of unicode --help from command line (Kai Willadsen)
   * Fix keyboard shortcut docs (Kai Willadsen)
   * Don't incorrectly show identical notification for changed folder
     comparisons (Kai Willadsen)

  Internal changes:

   * Requirements are now GTK+ 3.14, GtkSourceView 3.14 and GLib 2.36
   * Rewritten version control plugin API
   * Unified colour handling between linkmap, diffmap and file comparison
   * Move all textview drawing to a new GtkSourceView subclass, using the new
     GTK+ draw-layer API

  Translations:

   * Daniel Mustieles (es)
   * Gábor Kelemen (hu)
   * Jiri Grönroos (fi)
   * Josef Andersson (sv)
   * Marek Černocký (cs)
   * Piotr Drąg (pl)