Rewrite tokenizer and parse mechanism for structs to allow for values in base of structure.

[roarkanize]

This would mean rewriting completely the structure of the tokenizer to make it stateful by default, by adding a Tokenizer class which handles data management, etc. This class would have two main methods: tokenizeAlloc: which would use an allocator common to the structure to handle buffers and such, and tokenizeStatic: which would be used in comptime contexts, and would require to pass buffers from outside to keep valuable state. This would also require to split the parse function into a runtime and comptime version, since the tokenizer wouldn't be context agnostic. Whether this change is better or not will be seen when I get to write it.

There's also a need to rewrite the parsing functions to allow for values in the base of the structure, now they error with Invalid archetype at compile-time.