Now we run a pre-commit hook that tries to kill any process that locked
a file in target directory.
Updated timeout interval on windows from 120 to 90 minutes.
Fixes#243
- configured sccache on buildkite windows machines
- final result is sent to phabricator from "summary.py" that waits for both builds to complete
- extracted "add_url_artifact" to a runnable script
- reorganized code and fixed some of TODOs
