Version 0.4.0

Adds gzip support and fixes various bugs

• Blog post

New functionality

• Added support for gzip file format, thanks @kazjote! (#43)
• Added more logging (#31)
• Ensured OutOfMemoryError is logged (#29)

Bug fixes

• Fixed S3 outage causing infinite retry loop (#44)
• Changed sink_write_failed to storage_write_failed (#45)

Documentation, test and build

• Improved README (#42)
• Added Travis button into README (#41)
• Added .travis.yml file to repo (#40)