Improve CI caching (#416)

* Adjust linux distro to ubuntu 14.04

* Cache lib directory for speedy builds

* Fix path linking for default extensions

* Update reset

* Reset to head

* Improve caching

* Still run yarn in CI

* Update yarn before install

* Increase cache timeout

* Install vscode from vstar

* Undo data-dir changes to CLI, add back clean, remove unused CI func

* Remove additional flags added

* Remove unused dependency

* Reset vscode install dir so patching always works