[caching] InvalidationTests#test_with_io_mode
remove spurious file
[caching] Reduce the data volume size in InvalidationTests#test_with_io_mode
cache_utils.rb needs to include CacheXML
test_passthrough_fails_with_dirty_blocks
CacheStack#wait_for_clean_cache
test_with_io_mode() Wait for clean cache before switching to passthrough mode
[caching] More work on Invalidate tests
[caching] update invalidate tests for eras starting from 0, and increment_era rename
update README
update README
update README
update README
update README
update README
update README
update README
setup .dmtest if a list command is run (and not present)
[caching] InvalidateCBlocksTests