[alreq] Layout (flow direction) of math formula

tomerm has just created a new issue for https://github.com/w3c/alreq:

== Layout (flow direction) of math formula ==
In different countries in which Arabic script is used the direction of
 math formula is different. It is by all means different in those 
countries from rest of the world. 

In some countries it can be LTR:
x + y = z
While in others it can be RTL:
z = y + x

Some initial information on preferences in different countries is 
available from: 
​http://www.wiris.com/editor/docs/resources/arabic-numbers-countries

![image](https://cloud.githubusercontent.com/assets/5329257/23606912/80d7315c-026b-11e7-8cc3-36d4178df3f4.png)

![image](https://cloud.githubusercontent.com/assets/5329257/23606929/96967958-026b-11e7-8a0e-e27d5bd4725b.png)

Not all countries in which Arabic script is used are represented on 
the images above. 

Please view or discuss this issue at 
https://github.com/w3c/alreq/issues/100 using your GitHub account