simplified optimal parser

removed "cached" structure.
prices are now saved in the optimal table.

Primarily done for simplification.
Might improve speed by a little.
But actually, and surprisingly, also improves ratio in some circumstances.

lib/common/zstd_common.c

@@ -49,7 +49,7 @@ const char* ZSTD_getErrorString(ZSTD_ErrorCode code) { return ERR_getErrorString
 /*! g_debuglog_enable :
  *  turn on/off debug traces (global switch) */
 #if defined(ZSTD_DEBUG) && (ZSTD_DEBUG >= 2)
-int g_debuglog_enable = 1;
+int g_debuglevel = ZSTD_DEBUG;
 #endif