Update opus from 1.1 to 1.1.4

Define FLOAT_APPROX in Makefile and misc/msvc12/quake3.vcxproj.

code/opus-1.1/silk/float/structs_FLP.h

@@ -115,6 +115,7 @@ typedef struct {
 typedef struct {
     silk_encoder_state_FLP      state_Fxx[ ENCODER_NUM_CHANNELS ];
     stereo_enc_state            sStereo;
+    opus_int32                  nBitsUsedLBRR;
     opus_int32                  nBitsExceeded;
     opus_int                    nChannelsAPI;
     opus_int                    nChannelsInternal;