Fix problem with bl types, reactivate tests

[JKRhb]

This PR is a subset of #356, including the most important fix for @types/bl and reactivating the inactive tests. I'll rebase #356 once this one is merged – I had some problems getting the updated dependencies to work on Node 14 for some reason :/

[coveralls]

Pull Request Test Coverage Report for Build 3535908688

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+30.8%) to 91.83%

---

Totals
Change from base Build 3345980936:	30.8%
Covered Lines:	2848
Relevant Lines:	3059

---

💛 - Coveralls