Add speex to trunk/deps/third_party/....

speex/TODO

+For 1.2:
+Major points:
+- Make documentation match the actual code (especially jitter buffer, AEC and preprocessor)
+- Get AGC to work in fixed-point even if not totally converted
+- Stabilise all APIs (need feedback)
+- Short-term estimate in jitter buffer
+- Control delay in new AEC API.
+- NaN checks?
+- Better error reporting
+- Make kiss-fft 32-bit safe
+
+Minor issues:
+- Fix last frame of speexenc
+
+
+Post 1.2:
+improve float<->int conversion
+split encoder and decoder?
+Merge TriMedia stuff
+packet dump
+Do VAD properly
+--enable-{aec,preprocessor,jitter,resampler}
+
+Optimisations
+- Add restrict in a few places?
+- enable 4x4 version of pitch_xcorr() at least on some archs?
+- use __builtin_expect() (likely()/unlikely())
+
+Would be nice:
+Implement wideband split as IIR instead of QMF?
+
+Allocator override (speex_lib_ctl?)
+Fixed-point:
+  - VBR
+  - Jitter buffer
+  - AGC
+Denoiser:
+  - Better noise adaptation
+AGC:
+  - Use median filtering instead of "non-linear mean"?
+
+Standards
+-Complete Speex RTP profile
+-MIME type registration
+
+ideas:
+Peelable stream (double codebook, higher bands, stereo)
+LPC from spectral domain