api reference docs: include bpy.data in the main page since its used everywhere.

since this isnt a module its self its a little odd to do this but toctree cant make arbitrary cross-references.

Also added some usage examples: http://www.blender.org/documentation/250PythonDoc/bpy.data.html

source/blender/python/doc/examples/bpy.data.py

@@ -0,0 +1,28 @@
+import bpy
+
+
+# print all objects
+for obj in bpy.data.objects:
+    print(obj.name)
+
+
+# print all scene names in a list
+print(bpy.data.scenes.keys())
+
+
+# remove mesh Cube
+if "Cube" in bpy.data.meshes:
+    mesh = bpy.data.meshes["Cube"]
+    print("removing mesh", mesh)
+    bpy.data.meshes.unlink(mesh)
+
+
+# write images into a file next to the blend
+file = open(bpy.data.filepath.replace(".blend", ".txt"), 'w')
+
+for image in bpy.data.images:
+    file.write("%s %dx%d\n" % (image.filepath, image.size[0], image.size[1]))
+
+file.close()
+
+