Strings are needed for the handling of identifiers in the key/value
variable storage, so I've got them working first. I used the rope
pattern, which seems to be quite an interesting approach.
I'll add comparison checks later.
Adjusted how buckets are handled in all tests, could've been an issue
down the line.
Added the build instructions to README.md.
* expand() will only touch the memory once
* fixed missing if-else cascade at toy_routine.c:90
* unary negate will not optimise numbers unless the '-' character is immediately prior
* fixed broken test for unary negation of groups
The parser now correctly produces a workable AST. I think I'll skip
over the optimizer, and begin on the compiler next session. The
optimizer will act directly on the AST, but it isn't totally necessary.
Other tools can also operate on the AST, such as for debugging - I'll
have to ask what kinds are out there.
