Right-to-left Layout

[azizghuloum]

Hello, I have added rtl option to StackGrid:

• the purpose is to layout items from right-to-left instead of the default left-to-right
• The implementation is straightforward: instead of having the StackItem start with left:0 and transformX:${left}px, when rtl is true, we start with right:0 and transformX${-left}px.

I updated the demo to include a checkbox for switching RTL/LTR. Run npm start then check/uncheck the RTL checkbox and see how it works.

I added tests for this functionality.

The code passes npm test.

I updated the document at README.md.

[wadackel]

Hi @azizghuloum Thank you for contributes :smile: I was able to confirm that RTL is working :+1:

But, I think that it is unnecessary to change resize detection for this PR. Also, this change seems to have some problems. Is it possible to separate PR for resize detection?

[azizghuloum]

hello, I thought you'd be able to pull only the first two commits. I'll try to split them.