Windows: added methods for flashing windows; minor increment

ActiveQuery: ActiveGroupBy now returns an IActiveEnumerable of IActiv…

…eGrouping instances; ActiveSelect, ActiveSelectMany, and ActiveWhere have been reverted not to use disposable values caches; minor increment

ActiveExpressions: active expressions now cache their hash codes to i…

…mprove performance in certain scenarios, such as when they are used in keys in dictionaries; revision increment

Wpf: non-abstract classes sealed for performance; minor increment

ActiveExpressions, ActiveQuery: Cogs minimum

Windows: non-abstract classes sealed for performance; minor increment

ActiveExpressions, ActiveQuery, Collections.Synchronized, Collections…

…, Exceptions, Threading, Windows, WPF: NuGet updates

Threading: DataFlow minimum; revision increment
Exceptions: Cogs minimum; revision increment

Threading: non-abstract classes sealed for performance; minor increment

Reflection: non-abstract classes sealed for performance; minor increment

Expressions: non-abstract classes sealed for performance; minor incre…

…ment

ActiveExpressions, ActiveQuery, Collections.Synchronized, Collections…

…, Exceptions, Threading, Windows, WPF: NuGet updates

Threading: DataFlow minimum; revision increment
Exceptions: Cogs minimum; revision increment