Some fixes, also Trello

Moving from my old "todo.txt that never gets updated" to Trello. I can now confirm that I have fixed the Clang layout thing so now, Clang uses my layout when talking about a Wide type. I even succeeded in commanding it to use my size/alignment override attributes and the interface suggests that I can make it respect almost any layout I want, which is good.

In a not-really-related note, I also fixed arrays to now use bounds checking, and I am going to add unsafe array/pointer indexing soon. I also added a super-quick test for array interop with Clang that seems to have worked OK. I need to handle array-to-pointer decay, though.

One thing I feel that I need to make a big pass on soon is error handling. The parser errors, many of them are plain incorrect, and you can make a custom production in most places or override the default but you can't create new parser errors. Also the parser cannot handle multi-token operators in general, and the lexer cannot handle variable-length tokens in general, which are things I may or may not want to address. One of the things I can do with the new parser structure is, in theory, automatically create errors in many places which are of about the same quality as before, which would save a lot of effort.

And the analyzer errors, many of them are problematic, they're just throw std::runtime_error, which is somewhat difficult to deal with. I need to introduce special error handling for creating values of abstract bases and also been thinking about some kind of private_cast. Even the better errors are mostly just throw SemanticError. I need to factor out errors so they are a property of expressions or maybe also types that you can query and ignore if you want to.

For Clang types, I really managed to improve the description of the header a type came from. Now it should be almost always accurate as to the header the user actually requested to include from their Wide program that resulted in that type.

But, well, I got many things I need to do. At least this one will mean a break in fighting Clang for a while.