Use the libspeexdsp resampler

AFAICT it runs a little slower? but it's fixed point, and has much
better understood audio characteristics.

lib/speexdsp/include/speex/Makefile.am

@@ -0,0 +1,18 @@
+# Disable automatic dependency tracking if using other tools than gcc and gmake
+#AUTOMAKE_OPTIONS = no-dependencies
+
+# Historically, these headers were part of the speex package, so in order to
+# keep compatibility with existing software we need to keep installing them
+# in the same place as they were found then.  If new functionality, with new
+# headers, are added later, some thought should be given as to whether they
+# should instead go somewhere other than $prefix/include/speex.
+
+speexincludedir = $(includedir)/speex
+
+nodist_speexinclude_HEADERS = speexdsp_config_types.h
+
+speexinclude_HEADERS = speex_echo.h speex_jitter.h speex_preprocess.h speex_resampler.h \
+	speexdsp_types.h
+
+noinst_HEADERS=speex_buffer.h
+