Avoid a crash at shutdown.

	* glom/bakery/appwindow_withdoc.cc: on_menu_file_close():
	Close the document after hiding the UI, instead of the other way
	around because, with Gio::Application, hiding the window can cause
	it to be deleted, making any further use of it impossible.
Use the regular AX_BOOST_PYTHON configure.ac macro.

	* macros/ax_boost_python_murrayc.m4: Remove this heavily changed
	version of AX_BOOST_PYTHON because it is hard to use this while getting
	improvements to the official one.
	* macros/mm-python.m4: Remove this, which we used in
	AX_BOOST_PYTHON_MURRAYC.
	* macros/: Add the latest versions of ax_python_devel.m4,
	ax_boost_base.m4 and ax_boost_python.m4.
	* configure.ac: Use the official macros.
	* Makefile_libglom.am: Create some variables to build the
	flags and concatenate them together for simple use, and use them.
	* Makefile_tests.am: Use the variables here too.

Hopefully this does not cause any regressions. It should make it
easier to use python 3.