Websnap

Refactor
- update dev-dependencies
- improve README descriptions and usage instructions

Refactor
- improve boto3 S3 ClientError handling

Feat
- implement `timeout` argument that is the number of seconds to wait for response for
each HTTP request before timing out
Docs
- update README to include usage and default value for `timeout` argument

Fix
- correct classifiers

Fix
- remove invalid classifier

Docs
- add additional classifiers