* Add Node 10 to Travis config. Remove Node 6.

* Add Node 10 to Appveyor config. Remove Node 6.

* Remove node 9 from travis config.

* Increase mocha timeout.

* Update minimum Node version to 8.

* Update yarn to latest on Travis.

* Update old-node test to use Node 4.

* Increase mocha timeout in kitchensink-eject tests.

* Update yarn to latest on Appveyor.