feature to add user ability to set expiry base from Riak Object (ente…

…rprise edition only)

merge mv-tuning8 and mv-no-md-expiry from develop

merge of mv-delayed-bloom and warnings cleanup from develop branch

merge mv-expiry-manifest from develop. tag 2.0.29

rebase from develop, pulling mv-hot-backup

pull mv-mem-fences bug fix from develop

expiry iterator fix

make lz4 the default compression.

move expiry and hot_threads fix to 2.0 branch (for 2.0.24 tag)

leveldb develop, less expiry