Optimize copying elements from one list to another

[Stefan Glienke]

Currently when copying elements from one list to another there is no method such as GetRange in IList<T>. Using Skip(index).Take(count) is possible but creates an IEnumerable<T>. If using ToArray on that to pass to InsertRange does two "bad" things. First it puts out the elements one by one to the returned array and second it also does the same for InsertRange.

• TList<T>.InsertRange should be implemented to handle inserting an array better.
• IList<T> should get a method to easily get out a subrange of elements.
• IList<T> might get a CopyTo overload that takes an IList<T> (optional as the implementation of IList<T> might differ without direct access to the backing array)

[Stefan Glienke]

optimized AddRange and InsertRange for TList<T> (see issue #55)

→ <<cset d5370631ef6a>>

[Stefan Glienke]

added new method IList<T>.GetRange

→ <<cset 315468ee50e4>>