using readable-stream for db.createReadStream()
destroy() implementation for more backwards compatibility with the old api
close fires before end because of streams2, so use the end event instead
another data event no longer slips through with .pause(), remove the special case in the tests
end should fire 0 times when a stream is destroyed, not 1
set .readable and .writable so that the unit tests for readable stream pass
put the readable stream into flow mode in the test since it won't close otherwise (streams2ism)
call _cleanup() after encoding errors; all tests now pass!
implement changes from line comments
remove readable/writable cruft from tests
pass the highWaterMark parameter through
Merge branch 'master' of https://github.com/rvagg/node-levelup into streams2-read-stream