Feature/multi selection support + selection handler refacoring

[sonique6784]

• introduced a new ISelectableModel interface to store selection state, that need to be implemented by Cell, RH and CH in order to get a selection state
• now selection state sit in each Cell, which prevent rendering issues.
• introduced multiple selection
• restored shadow selection display

Note: previous implementation was storing selection state into [Cell|RowHeader|ColumnHeader]ViewRecycler, which leaded to inconsistency in rendering (because RecyclerViews are re-used).

[evrencoskun]

Hi @sonique6784

These days, I am pretty busy. So, I haven't reviewed your codes. That's why I didn't approve it yet. I just want to evaluate your approach by a cup of coffee at a more relaxed time.

After the reviewing process, I'll give you feedback.

Thank you very much for your collaboration. 👍

[sonique6784]

No worries, it's a big chunk of code, take your time. thanks

[sonique6784]

fixed conflict, ready to merge

[10erlosh]

Hi @evrencoskun any news on this?

[sonique6784]

@MGaetan89 @evrencoskun , I've fixed the conflicts and rested, it looks fine now.

[sonique6784]

[YoavSl]

@sonique6784 @evrencoskun Hey guys, any update on this? I really need the multiple row selection feature. Thanks a lot