S3-concat

- Any file that is larger then the min_file_size will not get combined with a smaller file anymore
- Issue was if a small file was to small, and the next file was larger then the min size it would still combine them
- Added threads for the main upload loop via the `main_threads` argument. This way even the large files will be uploaded using threads

- Fixed memory leak as noted in [issue 11](https://github.com/xtream1101/s3-concat/issues/11)

- Support quoted and un-quoted etag strings

- Allow binary files to be concat'd. NOTE: Will not work for all file types, only the ones that support it, like gzip.
- Added Changelog