Port to meson (#258)

* Port to meson

* plugin generation script: swtich to meson, update to python3, switch to libpeas, add some extra options, and cleanup

* clean up some build warnings

* kill xed-bugreport.sh with fire: it isn't used anymore, and probably doesn't even work

* update gzip command to avoid warnings on some systems and move appdata.xml to /usr/share/metainfo/ as that's where it's supposed to go now

* POTFILES.in: fix path that changed in the meson port, which was causing makepot to fail

po/POTFILES.in

@@ -65,7 +65,7 @@ plugins/docinfo/docinfo.plugin.desktop.in
 [type: gettext/glade]plugins/docinfo/docinfo.ui
 plugins/docinfo/xed-docinfo-plugin.c
 plugins/filebrowser/filebrowser.plugin.desktop.in
-[type: gettext/gsettings]plugins/filebrowser/org.x.editor.plugins.filebrowser.gschema.xml.in
+[type: gettext/gsettings]plugins/filebrowser/org.x.editor.plugins.filebrowser.gschema.xml
 plugins/filebrowser/xed-file-bookmarks-store.c
 plugins/filebrowser/xed-file-browser-messages.c
 plugins/filebrowser/xed-file-browser-plugin.c

po/meson.build

@@ -0,0 +1,3 @@
+i18n.gettext('xed',
+    preset: 'glib'
+)