some documentation added
methods FindBetween, IndicesOfAll, ToStringExpanded added and some minor changes, comments, etc
Added a bunch of new extension methods

GetKeys<T>
IndexOf<T>
FindNth
IndicesOf<T>
Overload of RemoveBetween to pass a func
IsBetweenMinAndMax
IsBetween
IEnumerable<IEnumerable<T>> Split<T>
InBetweenAny and several overloads
IndicesOfAll
Overload of Replace
FindAllBetween
Added Extensions.Object with a couple extension methods moved here
some tests...