The code and settings are kind of there. "Kind of" as there is no explicit setting to rotate the playarea. You can still tinker with the margin setting to get the size right. Check "userConfig.xml", section <vrMap> and in it there is margin. Positive value makes play area smaller. How to pretend to rotate it:
Size of your area is "width" and "depth" (these are in meters). In the game they are other way around. To make them right you have to set margin:
x = depth - width
y = width - depth
If your actual playarea is 3x2m, the line should be:
<margin x="-1" y="1"/>
If that doesn't work, switch values.
I am going to add a proper user interface and also to allow to rotate the playarea by any angle (the support for it is there, there is just no explicit setting available to set).