Merged r11123:11148 from jcorgan/np into trunk.

Merged r11123:11148 from jcorgan/np into trunk.

Adds --enable-python option to configure (defaults to yes).

Using --disable-python or --enable-python=no will cause only
C++ API targets to be created and installed.

Several new shared libraries are now created.  Where in the past,
the C++ objects of the actual gnuradio blocks that were in a component
were hidden inside their corresponding Python extension modules, these
are now split out into a libgnuradio-foo.so library, and the _foo.so
Python module is linked to that.  This has been the way several top-
level components have operated for some time, such as gr-audio-alsa
and gr-usrp and gr-usrp2.  This changeset applies that pattern to all
components.

C++ API users can use pkg-config to discover the cflags and libs
parameters needed to include and link against these libraries.

These components have not been tested:

gr-comedi
gr-audio-osx
gr-audio-windows

Passes distcheck.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@11150 221aa14e-8319-0410-a670-987f0aec2ac5