Re-enable the usage report (#1343)
Re-enable the usage report (#1343)

* Re-enable the usage report

Closes #1301

* Sync usage report goroutine with WaitGroup

Resolves https://github.com/loadimpact/k6/pull/1343#discussion_r388145629

* Add initialized VUs count to usage report

Partly resolves https://github.com/loadimpact/k6/pull/1343#discussion_r388141537

* Use full version in usage report

Resolves https://github.com/loadimpact/k6/pull/1343#discussion_r387787531

* Latest changes from code review (will squash)

* Fix nil pointer panic if timeout is reached

* Use channel to sync reportUsage goroutine

Resolves https://github.com/loadimpact/k6/pull/1343#discussion_r390826793

* Fix: only wait for report ch if it wasn't disabled
loadimpact/k6,loadimpact/k6