Changed references to encrypt/decrypt to mask/unmask.

This change clarifies the actual operation taking place.
Fleshed out Goji example to show how to apply a custom nosurf instance.
Fixed MaxAge usage.
Merge pull request #14 from elithrar/goji-example-extra

Fleshed out Goji example to show how to apply a custom nosurf instance.
Merge pull request #12 from elithrar/doc-changes

Changed references to encrypt/decrypt to mask/unmask.