Experimental option to build blender as a python module, rather then blender embedding python.

CMake build option WITH_PYTHON_MODULE, will build ./bin/bpy.so

This allows 'bpy' to be imported from python or other applications/IDE's which embed python, eg:
   python -c "import bpy ; bpy.ops.render.render(write_still=True)"

This runs in background mode and has similar restrictions to running a script:
   blender --background --python test.py

TODO:
 - install to site-packages with blender scripts
 - add support for imp.reload()

source/blender/python/intern/bpy.c

@@ -53,6 +53,8 @@
 
 #include "AUD_PyInit.h"
 
+PyObject *bpy_package_py= NULL;
+
 static char bpy_script_paths_doc[] =
 ".. function:: script_paths()\n"
 "\n"
@@ -161,7 +163,7 @@ static PyMethodDef meth_bpy_script_paths = {"script_paths", (PyCFunction)bpy_scr
 static PyMethodDef meth_bpy_blend_paths = {"blend_paths", (PyCFunction)bpy_blend_paths, METH_VARARGS|METH_KEYWORDS, bpy_blend_paths_doc};
 static PyMethodDef meth_bpy_user_resource = {"user_resource", (PyCFunction)bpy_user_resource, METH_VARARGS|METH_KEYWORDS, NULL};
 
-static void bpy_import_test(const char *modname)
+static PyObject *bpy_import_test(const char *modname)
 {
 	PyObject *mod= PyImport_ImportModuleLevel((char *)modname, NULL, NULL, NULL, 0);
 	if(mod) {
@@ -170,7 +172,9 @@ static void bpy_import_test(const char *modname)
 	else {
 		PyErr_Print();
 		PyErr_Clear();
-	}	
+	}
+
+	return mod;
 }
 
 /*****************************************************************************
@@ -235,5 +239,5 @@ void BPy_init_modules( void )
 	PyModule_AddObject(mod, meth_bpy_unregister_class.ml_name, (PyObject *)PyCFunction_New(&meth_bpy_unregister_class, NULL));
 
 	/* add our own modules dir, this is a python package */
-	bpy_import_test("bpy");
+	bpy_package_py= bpy_import_test("bpy");
 }