Replace base64 with cl-base64

[naryl]

base64 is only used by this library while cl-base64 is used by 23 others. It normally wouldn't be a problem but cl-base64 uses base64 as a nickname for its package so you can't load both base64 and cl-base64 in the same system. That's a huge problem because it means that you can't e.g. load sha1 which depends on base64 and drakma which depends on cl-base64.

[naryl]

@massung Is something wrong with this PR? Can you at least comment on it?

[massung]

Sorry, life taking priority at the moment. The PR is fine, but I'm not going to merge it.

While I can understand the desire in your PR, I wrote my base64 for myself and it's what I want to use for my packages. I fully control it as opposed to depending on someone else (which actually matters in the CL community as code appears and becomes abandoned quite frequently). And I use it in several packages of mine other than just the sha1 package, including some packages that use both it and sha1. Changing what this package uses would mean my other code now importing two different base64 libraries, which I don't want any more than you do. 😄

I could be convinced to rename my base64 package to something else, but I honestly haven't put much thought into that beyond asking myself if I'd be willing to do so.