buffer tells fiddle to create a buffer of a number of bytes.

skip_to tells fiddle to skip to some new offset. It's essentially an
unnamed buffer

Now it includes information about the package a symobl is in. The object
its in and the register its in. This allows better code generation in
the backend that's somewhat more organized.

This is for expressions which must be calculatable at compile time.

Have basic implementations down for coarse registers. Working on getting
bitfields supported.

This helps to catch bugs in the compiler, specifically ones related to
mixing up bits and bytes.

This makes deriving much easier and cleans up the messy contexts in
GenericTree and elsewhere at the cost of slightly more obtuse syntax.

It now converts normal data into JSON rather than using "show".