Bump `pyo3` dependency in `Cargo.toml`

Add quotes around `_tokio` module name declaration

Bump `setuptools-rust` version in CI requirements

Bump `setuptools-rust` version in CI requirements

Add `proc_macro_path_invoc` feature to fix the build

Update pytest-mock from 1.6.3 to 1.7.0 (#99)

Update pytest from 3.3.2 to 3.4.1 (#100)

Update sphinx from 1.7.0 to 1.7.1 (#101)

Update setuptools-rust from 0.8.3 to 0.8.4 (#102)

Merge pull request #96 from PyO3/pyup-update-sphinx-1.6.7-to-1.7.0

Merge pull request #98 from PyO3/pyup-update-ipdb-0.10.3-to-0.11

Update ipdb from 0.10.3 to 0.11

Update sphinx from 1.6.7 to 1.7.0

Merge pull request #95 from PyO3/pyup-update-pytest-sugar-0.9.0-to-0.9.1

Merge pull request #92 from PyO3/pyup-update-sphinx-1.6.6-to-1.6.7