Refactor: Change `FuncNode.name` to `FuncNode.func_id`

[thorwhalen]

The name name is problematic since it should be unique and used for internal purposes. More like a reference or id.

This refactor can be done while keeping back compatible (for now) by creating a @property called name that points to func_id.

Other name option: fid.

Could also have a **kwargs that keeps the possibility for using name in __init__ but I'd rather not.

Further (perhaps this should be a separate issue?) we may want to use func_id instead of the FuncNode instance itself in the DAG.graph. It's more readable, and less problems with hashing, sorting, etc.