add "engines" section to package.json. closes #27
tilde version locking
use graceful-fs to handle EMFILE errors
aws sdk fixed callback twice bug. closes #23
tweak defaults; update readme with a plan
reimplement uploadDir streaming style
setImmediate instead of nextTick
fix deleteRemoved check when uploading
default maxAsyncS3 30
reimplement downloadDir, streaming style
fix deleteRemoved behavior for downloadDir directories
downloadDir creates destination directory

if it does not exist. all tests pass now
remove stray log statement
Release 3.0.0
default maxAsyncS3 to 14, add expect 100-continue header to download
Release 3.0.1
upload to s3Path instead of path. fixes uploading on windows
Release 3.0.2
minor grammar update in README
uploadFile computes MD5 and sends bytes at same time.

closes #31