std::format support (microsoft#1025)

Avoid exception in observable IndexOf implementation (microsoft#1017)

Ignore errors during manual unregistration (microsoft#1005)

Use throw rather than abort() for guid parse failures (microsoft#992)

* Use throw rather than abort() for guid parse failures

Make `winrt::guid("...")` more useful at runtime by throwing on failure instead of aborting the program.

* Remove noexcept, add tests

* Revert operator== changes, revise tests

Co-authored-by: Kenny Kerr <kekerr@microsoft.com>

Harden put functions against misuse (microsoft#986)

Ensure the Xaml designer can find out WinMD (microsoft#982)

Ensure we don't override XamlLanguage if it's already set. (microsoft…

…#979)

When NuGet imports the props as part of PackageReference, it easy to end up in situations where the project file defines XamlLanguage before the C++/WinRT props are imported.

We shouldn't override if the value is already set.

Fix target override as it doesn't work when the target import order c…

…hanges. (microsoft#977)

* Fix target override as it doesn't work when the target import order changes.

* Fix mismatch.

* Minor updates.

Revert "Prevent inadvertent assignment to temporary object" (microsof…

…t#976)

Ingest updated Microsoft.Windows.WinMD to fix bug around "-exclude" (m…

…icrosoft#937)

* Ingest updated Microsoft.Windows.WinMD to fix bug around "-exclude" option.

* Clean up weirdness from VS updating the NuGet