[Discuss-gnuradio] Build process now uses "autotools"

[Eric Blossom]

Most of GNU Radio has been updated to use the GNU "autotools" for the
build process.  This means that Makefile.am's are the source of what
gets built. configure.in has been cleaned up, and now successfully
locates the QT includes and libraries.  You no longer need to set
QTDIR etc, and I strongly recommend that if you currently have it set,
you unset it.

In addition, the version of FFTW that was in the build tree has been
removed (it was at least two years out of date).  Now, before building
GNU Radio, you must download, build and install FFTW (Fastest FFT in
the West) from www.fftw.org.  It's a typical ./configure && make.

There are also new autoconf macros that locate the QT (now 2.x)
libraries and includes.  Please let me know if anybody runs into
problems trying to build.

I've fixed several bugs in the VrSigSource, VrFileSink and VrAudioSink
classes.  Audio output at 8KHz in mono and stereo is now working.
There are simple demos in gnuradio/src/pspectra/test/mono_audio_out
and stereo_audio_out.

I'm now working on getting the GUI stuff working.  It's *really*
sluggish, and is effectively not working.  I suspect the problem is in
the interaction between the Qt event loop and pspectra's scheduling loop.

I've been doing a lot of "de-crufting" of the built tree, and will be
moving stuff that's mostly likely never going to work again into "old"
directories.  Expect more build tree rearrangement.

Eric