Reverse interval not validated, then causes "Excessive recursion detected" exception

[felix-b]

Hi @jamarino!
Thanks again for this library, so far it does exactly what I need.
There was a minor issue I came across.
I happened to incorrectly add a reversed interval to QuickIntervalTree (from greater than to).
No validation errors occurred.
However, when attempted to run Query, I got a System.Exception saying "Excessive recursion detected".
If reverse intervals cause such behavior, wouldn't it be better to validate from and to in the Add method?
Could save the users some time looking for their bugs.

Here is the reproduction:

var tree = new QuickIntervalTree<int, string>();

tree.Add(100, 200, "abc");
tree.Add(10, 20, "def");
tree.Add(-100, -200, "uvw"); // incorrect; should be (-200, -100)
tree.Add(50, 150, "xyz");

tree.Query(-150, 150).ToArray(); // System.Exception here

System.Exception : Excessive recursion detected, aborting to prevent stack overflow. Please check thread safety.
   at Jamarino.IntervalTree.QuickIntervalTree`2.<Build>g__BuildRec|18_0(Int32 min, Int32 max, Int32 nodeIndex, Int32 recursionLevel)
   at Jamarino.IntervalTree.QuickIntervalTree`2.<Build>g__BuildRec|18_0(Int32 min, Int32 max, Int32 nodeIndex, Int32 recursionLevel)
   at Jamarino.IntervalTree.QuickIntervalTree`2.<Build>g__BuildRec|18_0(Int32 min, Int32 max, Int32 nodeIndex, Int32 recursionLevel)
.......

[felix-b]

Here is a pull request -- feel free to take a look:
#4

[jamarino]

Hello again, @felix-b !
What a silly oversight on my part! I'm glad the recursion check paid off... 😅

Your suggested changes look good to me and align well with the behaviour of RangeTree (for compatibility). I'll get 'em merged and published. Thank you!

[jamarino]

Merged, tagged, pushed and published ✔️ Just waiting for nuget.org to validate the upload, it should be available as version 1.2.1 momentarily.

Thanks again! Let me know if you encounter any other oddities or missing features 😃