doc: be specific about the unit of `maxBuffer`
doc: be specific about the unit of `maxBuffer`

The maxBuffer option was not self-documenting, so document the unit and
its effect.

PR-URL: https://github.com/iojs/io.js/pull/209
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node