Fix files with # in their filename.
Start at fixing #207: double-callback in certain error cases.
Use `once` to ensure all callbacks called once.

Should fix #207 completely, at the cost of swallowing some errors (e.g. if both request and response error).
Update dependencies.
Fix #237: potential double-callback in deleteMultiple.
Fix missing `return req` in `deleteFile`.
Release 0.9.0
Remove "Expect: 100-continue" headers

We weren't listening for the continue event, so this was kind of pointless and potentially problematic. Closes #241.
support extra (required) S3 pre-signed headers
Release 0.9.1
Merge branch 'master' into kaymbu