Innerscope

- Minor bugfix release for `innerself`. Check types more explicitly in `scoped_function`.

- Support generators.
- Escape repr text in html_repr.
- Raise if trying to wrap coroutine or async generator function.
- Support `ScopedFunction` as class method (added `__get__`).
- Add `builtin_names` attribute to `ScopedFunction` objects.
- More efficient reuse of data when binding variables to an existing `ScopedFunction`.

Add support for PyPy! Who else is surprised by this?

Add alternative method for getting the inner scope. Select with `method="trace"` in `scoped_func`. This may be useful when the default method fails for some reason. Generally, though, the default method (`method="bytecode"`) is still preferred. The "trace" method uses `sys.settrace`, so it will be slow and may cause havoc if there is another tracer (such as when debugging).

- Add support for Python 3.6 and 3.7.
- Support `func` keyword argument in `call` and `scope.call`.
- From 0.1.0, support defining classes and functions inside a function wrapped by `innerscope`.