The runtime rewrite visitor lowers things into runtime calls.

Also I broke out the semantic visitors into their own modules because
they're kinda big, at least some of them.

Fixes #10

Fixes #7

Fixes #6

Fixed some indentation issues in html output

Also include LLVM disassembly in test output and don't try running the
executable if the compilation failed

This should let me split tracking for semantic and emitting

I also made the compiler print out LLVM verification failures (we still
have some) and fixed the syntax for all the `run` tests so their `main`
functions are properly declared.

I need to figure out how to get overloads to make the rest of the
function tests work.

Also some nascent support for aggregate types and reduced debug logging

Getting a segfault with alloca?

This is not 100% accurate, but it should hopefully be good enough?

Well, a little, almost.

Also hooked up more type checking and made some more builtin types
explicit.

Cleaned up makefile handling of the bison generated parser

Technically this is both parsing and assembling the AST.

It passes at least a few tests.