Functions and variables relating to compilation and parsing have been moved to
`compiler.py` and `lex/__init__.py`, respectively. Those functions are
- `hy_parse` from `hy.importer` to `hy.lex`
- `hy_eval`, `ast_compile`, and `calling_module` from `hy.importer` to
`hy.compiler`
Closeshylang/hy#1695.