Sphere quadrature for orientation averaging

[GoogleCodeExporter]

Implement orientation averaging using quadrature over sphere surface,
according to ideas of Antti Penttila.

Original issue reported on code.google.com by yurkin on 24 Dec 2008 at 7:16

[myurkin]

/cc @anatheana

[myurkin]

Another relevant discussion is https://groups.google.com/forum/#!topic/adda-discuss/9gJTy2spRjo