fix weld vertices and primitive normal directions

Reverses order of vertices that weld op gives to make ngon so that it doesn't reverse the normal from what it used to be.
Fixed a bunch of inconsistent normals in primitives: circle (made normal(s) point up instead of down), uvsphere, icosphere, cylinder, and cone.

[Ender79, 2011-09-03 12:55:53]

Looks good

http://codereview.appspot.com/4959056/diff/1/source/blender/bmesh/operators/p...
File source/blender/bmesh/operators/primitiveops.c (right):

http://codereview.appspot.com/4959056/diff/1/source/blender/bmesh/operators/p...
source/blender/bmesh/operators/primitiveops.c:300: vec[0]= -dia*sinf(phi);
Since it seems essentially random which direction the normal will point when
extruding a face from a wire edge, it seems fine to flip it here if that fixes
the issue. But I wonder if this will start to show up in other places (addons).
I guess if it becomes a real problem, maybe we can flip the "randomness" so it
is always random the other way.

http://codereview.appspot.com/4959056/diff/1/source/blender/bmesh/operators/p...
source/blender/bmesh/operators/primitiveops.c:506: f = BM_Make_QuadTri(bm,
cent1, v1, firstv1, NULL, NULL, 0);
All these quadtri swaps look right for sure. The initial implementation before
these changes likely just shows how Blender's mode of drawing two-sided faces by
default can lead to thinking everything is all right when it in fact is not.