Code generator (parsing) needs fixing to be compatible with newer versions of the QAPI spec

[connorkuehl]

The QAPI spec has developed quite a bit since go-qemu was last generated.

For example, there are now CONFIG switches where fields will be included or excluded based on the QEMU build config. There are also some teething pains where the QAPI schema has more whitespace between a struct comment and the struct that it documents which causes the parser to fail, when it shouldn't.

Reference for the code generation schema: https://www.qemu.org/docs/master/devel/qapi-code-gen.html

Related to #189