pjproject_bundled: Add MALLOC_DEBUG capability

pjproject_bundled will now use the asterisk memory debugging APIs
if MALLOC_DEBUG is turned on in menuselect.

Because this required stubs for the executable programs and the python
bindings, some Makefile reorganization was needed to properly handle
the dependencies.  As a result, the makefile now individually makes
each of the pjproject libraries separately instead of making them all
in 1 shot.  The only visible change is that there are separate status
lines printed for each library instead oif 1 for all libs.  Also, the
making of the pjproject dependency files was eliminated.  They're not
needed for building unless you're actively modifying pjproject source
files and it makes the build process faster.  Finally, any issues with
parallel builds should be resolved again making the build faster.

Change-Id: Icc5e3d658fbfb00e0a46b44c66dcc2522d5171b0