Update libsndfile to 1.0.29pre2+git

This pulls in MANY (over 890) changes compared to our
from our current 1.0.24 version.

lib-src/libsndfile/README

@@ -1,4 +1,4 @@
-This is libsndfile, 1.0.24
+This is libsndfile, 1.0.28
 
 libsndfile is a library of C routines for reading and writing
 files containing sampled audio data.
@@ -20,6 +20,9 @@ Bormann. Their original code can be found at :
 The src/G72x directory contains code written and released by Sun Microsystems
 under a suitably free license.
 
+The src/ALAC directory contains code written and released by Apple Inc and
+released under the Apache license.
+
 
 LINUX
 -----
@@ -32,9 +35,12 @@ If you really do need to compile from source it should be as easy as:
 		make
 		make install
 
-Since libsndfile optionally links against libFLAC, libogg and libvorbis, you
-will need to install appropriate versions of these libraries before running
-configure as above.
+Since libsndfile optionally links against libFLAC, libogg, libvorbis and
+libopus, you will need to install appropriate versions of these libraries
+before running configure as above.
+
+You can use CMake now to build under Linux, also under Windows and MacOS, see
+README.md for details. CMake toolchain is usable, but still exterimental.
 
 
 UNIX
@@ -44,11 +50,13 @@ Compile as for Linux.
 
 Win32/Win64
 -----------
-The default Windows compilers are nowhere near compliant with the 1999 ISO
-C Standard and hence not able to compile libsndfile.
 
-Please use the libsndfile binaries available on the libsndfile web site.
+Official Windows binaries are compiled with Autotools and MinGW, but you can use
+CMake to generate solution for Visual Studio. Details are described in
+README.md.
 
+It is still recommended to use the libsndfile binaries available on the
+libsndfile web site.
 
 MacOSX
 ------
@@ -63,3 +71,6 @@ The libsndfile home page is at :
 
 	http://www.mega-nerd.com/libsndfile/
 
+Bugs and support questions can be raised at :
+
+	https://github.com/erikd/libsndfile/