fix conflicting abstract-leveldown dependency
wrap iterator in a javascript-function
prepare to buffer
manually buffer up some data before returning
move some code from the old buffering iterator
use nextBuffering to read multiple values each time
remove .next() rename nextBuffering -> .next()
wrap leveldown in js (removing some ugliness from index.js)
cleanup
use configurable highWaterMark as limit for buffer
fixes based on review
style/cleanup
fix levelup read-stream-test: run callback from next in next tick
Revert "fix levelup read-stream-test: run callback from next in next tick"

This reverts commit 6ec8767b06170090b8ecfdf49b515f9b6f0b4d27.
inherit from abstract-leveldown
inherit from AbstractLevelDOWN & AbstractIterator
remove some c++
use abstract-leveldown for ChainedBatch
remove unused macro
remove some c++ from batch