Get rid of "using namespace std" everywhere

[orgads]

Use consistent scoping.

[orgads]

@wdoekes The failures here are unrelated to my changes. Can you please approve it?

[wdoekes]

No sneaky ifunc additions here, right? ;P

[orgads]

🤣🤣

[wdoekes]

There are some other changes than just adding std:: (adding auto, replacing heap with stack alloc), but I guess it's fine. We did auto already, I see. And the stack is only for the better here.

[orgads]

I preferred changing to auto rather than std::map<whatever>::iterator...