New experiment: Perceptual Vector Quantization from Daala

PVQ replaces the scalar quantizer and coefficient coding with a new
design originally developed in Daala. It currently depends on the
Daala entropy coder although it could be adapted to work with another
entropy coder if needed:
./configure --enable-experimental --enable-daala_ec --enable-pvq

The version of PVQ in this commit is adapted from the following
revision of Daala:
https://github.com/xiph/daala/commit/fb51c1ade6a31b668a0157d89de8f0a4493162a8

More information about PVQ:
- https://people.xiph.org/~jm/daala/pvq_demo/
- https://jmvalin.ca/papers/spie_pvq.pdf

The following files are copied as-is from Daala with minimal
adaptations, therefore we disable clang-format on those files
to make it easier to synchronize the AV1 and Daala codebases in the future:
 av1/common/generic_code.c
 av1/common/generic_code.h
 av1/common/laplace_tables.c
 av1/common/partition.c
 av1/common/partition.h
 av1/common/pvq.c
 av1/common/pvq.h
 av1/common/state.c
 av1/common/state.h
 av1/common/zigzag.h
 av1/common/zigzag16.c
 av1/common/zigzag32.c
 av1/common/zigzag4.c
 av1/common/zigzag64.c
 av1/common/zigzag8.c
 av1/decoder/decint.h
 av1/decoder/generic_decoder.c
 av1/decoder/laplace_decoder.c
 av1/decoder/pvq_decoder.c
 av1/decoder/pvq_decoder.h
 av1/encoder/daala_compat_enc.c
 av1/encoder/encint.h
 av1/encoder/generic_encoder.c
 av1/encoder/laplace_encoder.c
 av1/encoder/pvq_encoder.c
 av1/encoder/pvq_encoder.h

Known issues:
- Lossless mode is not supported, '--lossless=1' will give the same result as
'--end-usage=q --cq-level=1'.
- High bit depth is not supported by PVQ.

Change-Id: I1ae0d6517b87f4c1ccea944b2e12dc906979f25e
diff --git a/av1/decoder/decoder.c b/av1/decoder/decoder.c
index c3099ba..7547656 100644
--- a/av1/decoder/decoder.c
+++ b/av1/decoder/decoder.c
@@ -33,7 +33,10 @@
 
 #include "av1/decoder/decodeframe.h"
 #include "av1/decoder/decoder.h"
+
+#if !CONFIG_PVQ
 #include "av1/decoder/detokenize.h"
+#endif
 
 static void initialize_dec(void) {
   static volatile int init_done = 0;