Make installing to a PREFIX easier and add appdata

misc/unix/grafx2.appdata.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<component type="desktop-application">
+  <id type="desktop">grafx2.desktop</id>
+  <metadata_licence>CC-0</metadata_licence>
+  <project_license>GPL-2.0 and CeCILL-2</project_license>
+  <name>GrafX2</name>
+  <summary>A bitmap paint program specialized in 256 color drawing</summary>
+
+  <description>
+    <p>
+      GrafX2 is a bitmap paint program inspired by the Amiga programs ​Deluxe Paint
+      and Brilliance. Specialized in 256-color drawing, it includes a very large
+      number of tools and effects that make it particularly suitable for pixel
+      art, game graphics, and generally any detailed graphics painted with a
+      mouse.
+    </p>
+  </description>
+
+  <screenshots>
+    <screenshot type="default">
+      <caption>Zoom functionality</caption>
+      <image>http://grafx2.chez.com/data/medias/screenshots/04-zoom.png</image>
+    </screenshot>
+    <screenshot>
+      <caption>Grid mode</caption>
+      <image>http://grafx2.chez.com/data/medias/screenshots/06-grid.png</image>
+    </screenshot>
+    <screenshot>
+      <caption>The splash screen</caption>
+      <image>http://grafx2.chez.com/data/medias/screenshots/01-splash.png</image>
+    </screenshot>
+  </screenshots>
+
+  <url type="homepage">http://grafx2.tk</url>
+  <url type="bugtracker">https://pulkomandy.tk/projects/GrafX2</url>
+  
+  <provides>
+    <binary>grafx2</binary>
+  </provides>
+</component>