* Added new statistics and refactored to allow ioptions to be passed around as required to access environment and statistics pointers (and, as a convenient side effect, info_log pointer).

* Prevent incrementing compression counter when compression is turned off in options.

* Prevent incrementing compression counter when compression is turned off in options.

* Added two more supported compression types to test code in db_test.cc

* Prevent incrementing compression counter when compression is turned off in options.

* Added new StatsLevel that excludes compression timing.

* Fixed casting error in coding.h

* Fixed CompressionStatsTest for new StatsLevel.

* Removed unused variable that was breaking the Linux build