v0.12.0 - Multiple extension methods and bugfixes

• Created Nixill.Collections.Grid.CSV.CSVObjectCollection<T> class
• Made the class Nixill.Collections.Grid.CSV.CSVParser static
• Fixed error with null value in CSVParser.CSVEscape (now returns empty string)
• Fix SemVer.CompareTo(SemVer)
• Added several EnumerableUtils extension methods:
  • IEnumerable<Task>.NoWait() - Executes all tasks. Returns nothing and cannot be awaited.
  • IEnumerable<Task>.WaitAllNoReturn() - Executes all tasks. Returns Task; can be awaited but returns no values.
  • IEnumerable<Task>.WaitAllReturns() - Executes all tasks and returns their values.
  • IEnumerable<TInput>.Sum<TInput, TOutput>() (when TInput : IAdditionOperators<TInput, TOutput, TOutput>, IAdditiveIdentity<TInput, TOutput>) - Returns the sum of all the elements. (Also a version where TInput and TOutput are the same type.)
  • IEnumerable<TInput>.Average<TInput, TOutput>() (when TInput : IAdditionOperators<TInput, TOutput, TOutput>, IAdditiveIdentity<TInput, TOutput> and TOutput : IDivisionOperators<TOutput, int, TOutput>) - Returns the average of all the elements, throwing an exception if the input sequence is empty. (Also a version where TInput and TOutput are the same type.)
  • IEnumerable<TInput>.Average<TInput, TOutput>(TOutput) (when TInput : IAdditionOperators<TInput, TOutput, TOutput>, IAdditiveIdentity<TInput, TOutput> and TOutput : IDivisionOperators<TOutput, int, TOutput>) - Returns the average of all the elements, or a default value if the input sequence is empty.
• Fix FileUtils.FileCharEnumerator(string) to close the stream reader when done.