Vector bound check bug has been fixed in python's layer
Tweaks to the DirectoryLayer

- added some documentation
- don't fail with nullref when removing empty parent
- testing some new extensions methods...
Fixed the flow of FdbAsyncMode with async operators

- Where/Filters should replace Head with Iterator because they can read more from the db to output one result
- Ensure that all foreach(...) type operators pass in All mode
- Some methods where not flowing the mode to the source
LINQ2FDB: ToEnumerable() should be on FdbAsyncSequenceQuery<T> and use the mode All
Renamed FdbTuple.FromArray/FromEnumerable to FdbTuple.CreateRange

- Using the same naming conventions as the the Microsoft.BCL.Immutable library for creating tuples from collections
- CreateRange(...) will now COPY the array / collection
- Added CreateRange<T>(...) that helps converting T[] into object[] arrays
- Wrap(..) can be used to wrap existing arrays but they are DANGEROUS