Add async version of matchPath

[jonaskello]

Needed for webpack plugin to support cached filesystem.

[coveralls]

Coverage decreased (-3.0%) to 75.904% when pulling 457f0d0 on feature/add-async into f1d967f on master.

[coveralls]

Coverage decreased (-3.0%) to 75.904% when pulling 4fad84d on feature/add-async into f1d967f on master.

[coveralls]

Coverage decreased (-13.7%) to 60.191% when pulling e67e867 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage decreased (-8.5%) to 65.479% when pulling 6a97e3e on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage decreased (-8.5%) to 65.479% when pulling 6a97e3e on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage decreased (-8.5%) to 65.479% when pulling 6a97e3e on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+1.003%) to 74.933% when pulling f6c4a35 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+1.006%) to 74.936% when pulling 847d314 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+3.7%) to 77.58% when pulling 1650d5f on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+1.6%) to 75.49% when pulling c5a26a7 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage decreased (-2.4%) to 71.504% when pulling a7c4c79 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+0.6%) to 74.51% when pulling 228a73b on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+0.9%) to 74.78% when pulling 3408253 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+0.9%) to 74.78% when pulling 3408253 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+0.9%) to 74.78% when pulling 3408253 on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage decreased (-0.9%) to 73.077% when pulling 23037de on feature/add-async into 6c50d47 on master.

[coveralls]

Coverage increased (+1.2%) to 75.138% when pulling 73391d2 on feature/add-async into 6c50d47 on master.