Add mtPaint docs && screenie

Signed-off-by: Morgan Lee <chewymorgy@gmail.com>

source/3/3.3/3.3.1/mtpaint.rst

@@ -0,0 +1,21 @@
+Chapter 3.3.4: mtPaint
+======================
+
+Description
+-----------
+mtPaint (Mark Tyler's Painting Program) is a painting program which Mark Tyler developed from scratch so he could easily create pixel art and manipulate digital photos.
+
+It uses the GTK+ toolkit (version 1 or 2) and runs on PC's via the GNU/Linux or Windows operating systems. Due to its efficient design it can run on older PC hardware (e.g. a 200MHz CPU and 16MB of free RAM).
+
+Screenshot
+----------
+.. image:: mtpaint-screenshot.png
+   :width: 80%
+
+Version
+-------
+Lubuntu currently ships with mtPaint v3.4.0.
+
+How to launch
+-------------
+Go to the Applications Menu > Graphics > mtPaint graphic editor

source/3/3.3/accessories.rst

@@ -7,6 +7,7 @@ This chapter contains the list of accessories installed by default.
    :maxdepth: 2
    :titlesonly:
 
+   3.3.1/mtpaint
    3.3.3/galculator
    3.3.4/leafpad
    3.3.6/xpad