Calculating statistics from .3d files

[David Loeffler]

Just realised that there is an error in the code. Line 266 currently reads

> 		if(sa >= 0)

and it should read

>		if(sa > 0)

(I started with the latter, then changed it to the former as it was 
producing strange results on surveys which all of whose legs were 
collinear; but this had a side effect I hadn't anticipated causing the 
program to mishandle equates and produce wrong results.)

Sorry guys.

David