Fix leak of options attributes.
Don't die when reopening DB.
Don't hold onto options in DB. Hang onto block_cache and filter_policy and free those on DB close.
Merge pull request #88 from ggreer/dont_leak_options_attrs

Fix leak of options attributes.
update abstract-leveldown
upgrade to leveldb 1.15.0
remove -Wno-unused-local-typedefs
Merge branch '0.11-wip' of github.com:rvagg/node-leveldown into 0.11-wip