changed all functions to switch to their 2nd order taylor expansion when evaluating around 0, since things oscillated wildly otherwise
changed all functions to switch to their 2nd order taylor expansion when evaluating around 0, since things oscillated wildly otherwise


git-svn-id: 9e9401559e51101c165cdce4d49b411eb20436ed@1347 3d70eeeb-363e-0410-a505-8a46323a89f2

Slicer/teem,BRAINSia/teem,Slicer/teem,Slicer/teem,Slicer/teem,BRAINSia/teem,BRAINSia/teem,BRAINSia/teem,BRAINSia/teem,Slicer/teem