Publish the Athena JAR using SBT.

[Ian Macalinao]

We should use sbt publish to publish our Athena JAR. Our current method is pretty insecure, as we are uploading to a public S3 bucket. Furthermore, it's a bit hacky and a little too custom for my taste.

See https://github.com/asunaio/asunasan for an example on how this is done.

Also, verify that the Aincrad S3 bucket is private to only us. If it isn't, fix it.

Please fix #3 first.

[Pradyuman Vig]

Aincrad is private.