New analizer suggestion: ConfigureAwait checking

[DavidKarlas]

Libraries writers who use async/await (e.g. roslyn) use almost always .ConfigureAwait(false). I this case it would make sense to have some analizer like this: http://blog.cincura.net/233476-checking-for-configureawait-false-automatically/

If WPF or other UI developers don't like this warnings they can always disable this analizer... or use .ConfigureAwait(true) to silence it if 99% of other await have to use .ConfigureAwait(false).