when v1.6.0 Release Notes

    • 🆕 New [when.join](docs/api.md#whenjoin) - Joins 2 or more promises together into a single promise.
    • 📄 [when.some](docs/api.md#whensome) and [when.any](docs/api.md#whenany) now act like competitive races, and have generally more useful behavior. Read the discussion in #60.
    • Experimental progress event propagation. Progress events will propagate through promise chains. [Read the details here](docs/api.md#progress-events).
    • Temporarily removed calls to Object.freeze. Promises are no longer frozen due to a horrendous v8 performance penalty. Read discussion here.
      • IMPORTANT: Continue to treat promises as if they are frozen, since freeze() will be reintroduced once v8 performance improves.
    • when/debug now allows setting global a debugging callback for rejected promises.