What's new in 2.2.0
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* StartsWithInvariant/EndsWithInvariant/IndexOfInvariant/LastIndexOfInvariant methods.
* Add frameworks support: .NET Standard 1.6, .NET Standard 1.5, .NET Core 1.0, .NET Core 1.1.
* Extend .NET 2.0, .NET 3.5 and .NET 4.0 support.
* Use Theraot.Core dependency for older frameworks targeting.
* Remove System.ValueTuple dependency.
* Add DictionaryCollectionExtensions
* Fluent assertions
* Limited .NET framework 2.0 support
* ExceptionExtensions.ToDiagnosticString[Async] improvements
* DictionaryExtensions.GetOrAddAsync/AddOrUpdateAsync
* LazyDictionary ctors and Create with initial data supplied
* Performance improvements in Fn class
* string.StartsWith/EndsWith with specific char matching
* Additional code annotations added
* Fixes, refactoring and code cleanup