Collapse/fold/hide regions in linear view

[plafosse]

Regions in linear view should be collapsable and should have a default preference. By default things like ELF/PE headers, IAT/PLT entries should be collapsed. Should also implement keystrokes and clickable buttons to expand/collapse these regions.

Proposed foldable items:

• [ ] Structures and arrays
• [ ] Sections?
• [ ] Code blocks, e.g. if statement branches

[plafosse]

This also applies to structures and arrays.

[ccarpenter04]

I would love to see this implemented

[yrp604]

With HLIL and linear view this would be really nice. Right now if you have an indent block that spans more than a screen width in HLIL's linear view, it can be very difficult to find the indentation points where blocks are terminated.

[psifertex]

There's a feature branch experimenting with adding indentation lines as well to help with this particular problem, though there's been some debate internally as to the right way to do it.

[jonpalmisc]

This would ideally include the ability to fold code blocks, e.g. long if statements. (#3311)