move initialization to io subclasses
add io key validation
add callbacks after io close
full_path->execute_in_full_path + break down method
S3 buckets
formatting
Test partially passing, attempt to do encoding cohersion
basic tests passing, need more robust connection, io tests
add bucket_io test
add remote test for s3 bucket

Can be tested with:
AWS_ACCESS_KEY_ID="" AWS_SECRET_ACCESS_KEY="" S3_BUCKET_NAME="" be rake spe
add test for eager load, fix io method name
add test for io.abort
make aws-sdk a soft dependancy
make s3_bucket store a config like other config vars