Add GTK config

Removes padding from GNOME apps on tiling window managers.

gtk/gtk-3.0.configdir/gtk.css

@@ -0,0 +1,10 @@
+.window-frame, .window-frame:backdrop {
+    box-shadow: 0 0 0 black;
+    border-style: none;
+    margin: 0;
+    border-radius: 0;
+}
+
+.titlebar {
+    border-radius: 0;
+}

gtk/gtk-3.0.configdir/settings.ini

@@ -0,0 +1,16 @@
+[Settings]
+gtk-theme-name=iris
+gtk-icon-theme-name=Numix-Circle
+gtk-font-name=Cantarell 11
+gtk-cursor-theme-name=Adwaita
+gtk-cursor-theme-size=0
+gtk-toolbar-style=GTK_TOOLBAR_BOTH
+gtk-toolbar-icon-size=GTK_ICON_SIZE_LARGE_TOOLBAR
+gtk-button-images=0
+gtk-menu-images=0
+gtk-enable-event-sounds=1
+gtk-enable-input-feedback-sounds=1
+gtk-xft-antialias=1
+gtk-xft-hinting=1
+gtk-xft-hintstyle=hintslight
+gtk-xft-rgba=rgb