Tile Grid Object Collection needs some rework

[gilbdev]

Describe the bug

Today, i tried to use Tile Grid Object Collection ..

first of all : "Centered" option is bugged (missing parenthesis in the code arround Column - 1)
secondly : does not derive from BaseObjectCollection or GridObjectCollection
third (link to 2nd) : the position is updated constantly in the Update() function (performance issue)
fourth : typo in property LayoutDireciton

lastly, not sure what the difference is from Grid, and documentation is not very explicit (and misleading, as we can think it inherit from Grid) :

TileGridObjectCollection.cs provides some additional options to GridObjectCollection

Expected behavior

minimal : fix 1 and 4
optimized: inherit from Grid and document better to tell what are the differences
radical : remove TileObjectCollection

Your Setup (please complete the following information)

• Unity Version [2018.4.9f1]
• MRTK Version [2.1 stabilization]

Additional context

I can help and make a PR based on decision

[stale]

This issue has been marked as stale by an automated process because it has not had any recent activity. It will be automatically closed in 30 days if no further activity occurs. If this is still an issue please add a new comment with more recent details and repro steps.

[julenka]

Fixed by #6550 and subsequent improvements to GridObjectCollection