configurable

rb://1111
approved by: Sunny Bains

(based on facebook contribution)

New Parameters:
===============

innodb_compression_level:
default 6 range 0 - 9. dynamic. specifies the compression
level used by zlib.

innodb_log_compressed pages:
default true (same as current behaviour): specifies whether or not we
need to store compressed index page images in the redo after we make
such a change that causes recompression.

This patch introduces two new redo log rec types:

+#define MLOG_ZIP_PAGE_COMPRESS_NO_DATA         ((byte)52)/*!< compress an index page
+                                               without logging it's image */ 
+#define MLOG_ZIP_PAGE_REORGANIZE ((byte)53)    /*!< reorganize a compressed
+                                               page */