Fixes and new AsReadOnlyList.

- Monitor for WaitOnErrorFromBackgroundThreadsPending
used Pulse instead of PulseAll.
- Fixed name of WaitOnErrorFromBackgroundThreadsPending (missing
"Pending" suffix).
- New .Net40/45 AsReadOnlyList extension method.
- Version is now 2.8.5
Fix AsReadOnlyList...

- IList<T> is NOT IReadOnlyList<T>. Only List<T> is...