Memory Editor: Added extended features

[Dimoks]

Memory Editor: Added extended selection features, scrolling, copy functionality, address input options, search panel, and UTF-8 display.

[ocornut]

Hello, Thanks for the PR. This looks generally desirable, but seems a bit large to be reviewed easy. Do you think this could be split into multiple commits, one per feature?

[Dimoks]

Separated by features. Will this be acceptable?

[ocornut]

Seems good. Thanks! Will ease review. I'm currently away for a little bit of time but I'll catch up with this eventually.

[ocornut]

You seem to frequently use PushID()/PopID() for cases where a simple use of ## in the string would work better.

e.g.

            ImGui::PushID("CopyDec_Preview");
            if (ImGui::SmallButton("Copy"))
                ImGui::SetClipboardText(buf);
            ImGui::PopID();

could be:

            if (ImGui::SmallButton("Copy##CopyDec"))
                ImGui::SetClipboardText(buf);

"Memory Editor: Add copy functionality to DrawPreviewLine."

Would be better implemented with a right-click menu + tooltip with long timer. The 3 duplicate code could be in 1 function.

There are quite a few features here, I'm starting to be unsure if we should be adding all of them to this mini library. I'll investigate it more later.

[Dimoks]

I didn't like adding the ID myself. I wasn't aware of ##. It seems inappropriate to introduce a context menu here; it's much easier to press a button next to the value than to navigate through the menu.