Chore: stop to :use packages

[kilianmh]

• stop to use transitive dependencies
• import-from utilized symbols instead

[hanshuebner]

Rather than importing the symbols, it would be preferable to qualify their usage. I would not merge this PR as it does not add any value but makes future changes harder.

[kilianmh]

The main importance is to not :use other packages.

it would be preferable to qualify their usage

Now the symbols from external packages are qualified instead of being imported in the defpackage. @hanshuebner

On Linux with SBCL-2.3.2 and Allegro-10.1 loading and testing works fine. Especially on Lispworks it should be tested whether it works. (due to when-let from alexandria/lw)

[hanshuebner]

The main importance is to not :use other packages.

I fail to see the importance at this point, but now the change looks more maintainable than the previous explicit imports.

[stassats]

Seems like a non-issue. We'll deal with any potential future conflicts when they arise.