Missing base64 encoding

[jumarko]

The buddy.core.codecs imports the org.apache.commons.codec.binary.Base64 class but doesn't use it at all.
It would be convenient if there were base64->bytes and bytes->base64 functions doing conversion from/to base65 encoded string.

Can submit a patch if there's any interest in this.

[niwinz]

The base64 codecs are in a different namespace: https://github.com/funcool/buddy-core/blob/master/src/buddy/core/codecs/base64.clj