WIP of s3 keydb driver
Corrected problems with s3 directory handling, added streaming for set, temporarily adding s3 examples file.
Removed s3 test credentials
converted tests from s3-examples.js.tmp into the proper drivers-s3.js mocha test
Thought I'd removed the environment var reading in s3 driver yesterday but noticed they were back!  Now they're gone for real!
Added the size, etag, lastModified to the meta info because it was easy and because jsDAV makes use of it.
jsDAV commented that empty files could be a problem so added tests for those.
made s3 bucket name a driver option
Merge pull request #3 from apto/105-proxy-content-from-s3

105 proxy content from s3