Replace lbase64 with LuaSockets mime.b64?

[imolein]

Is there a specific reason why lbase64 is used?

Why not use the b64() function of LuaSockets mime module and get rid of this dependency? As far as I tested it on my system, there no difference in performance or something like this. And LuaSocket is not unmaintained like lbase64.

[JakobGreen]

Good catch! I just fixed this and updated the rock you submitted in #23

[imolein]

Niceeeee. I wanted to do that tomorrow because I'm too tired. So thank you :)