approximateSize() tests
style tweaks
Merge branch '0.1-wip' of github.com:rvagg/node-leveldown into 0.1-wip

Conflicts:
	src/database.cc
added batch tests
fix keyless batch(), symbol macros to LU_SYMBOL
further batch() tests
move createIterator to db.iterator, add tests
added uber test suite for iterator()

copied the logic from LevelUP read-stream-test.js
add namespace macros