Test u turn back from a number of positions, checking also half a u turn
back to ensure we're turning in the correct direction.

sdr> /program = Program.PLUS ; setFormation(Formation.SQUARED_SET)
|      3Gv  3Bv
| 
| 4B>            2G<
| 
| 4G>            2B<
| 
|      1B^  1G^
sdr> u turn back          
|      3G^  3B^
| 
| 4B<            2G>
| 
| 4G<            2B>
| 
|      1Bv  1Gv
sdr> do half of a u turn back
|      3G>  3B<
| 
| 4Bv            2Gv
| 
| 4G^            2B^
| 
|      1B>  1G<
sdr> touch 1/4
|      3B^  3Gv
| 
| 4G>            2B>
| 
| 4B<            2G<
| 
|      1G^  1Bv
sdr> boys run
|      3Gv  3Bv
| 
| 4B>            2G<
| 
| 4G>            2B<
| 
|      1B^  1G^
sdr> heads lead right
| 4B>  3G<  1B>  2G<
| 
| 4G>  3B<  1G>  2B<
sdr> extend
| 4B>  1B>
| 
| 3G<  2G<
| 
| 4G>  1G>
| 
| 3B<  2B<
sdr> do half of a u turn back
| 4Bv  1Bv
| 
| 3G^  2G^
| 
| 4Gv  1Gv
| 
| 3B^  2B^
sdr> touch 1/4
| 3G>  2G>
| 
| 4B<  1B<
| 
| 3B>  2B>
| 
| 4G<  1G<
sdr> extend
|      3G>
| 
| 4B<  1B<  2G>
| 
| 4G<  3B>  2B>
| 
|      1G<
sdr> u turn back
|      3G<
| 
| 4B>  1B>  2G<
| 
| 4G>  3B<  2B<
| 
|      1G>
sdr> do half of a u turn back
|      3Gv
| 
| 4Bv  1B^  2Gv
| 
| 4G^  3Bv  2B^
| 
|      1G^
sdr> u turn back
|      3G^
| 
| 4B^  1Bv  2G^
| 
| 4Gv  3B^  2Bv
| 
|      1Gv
sdr> face right
|      3G>
| 
| 4B>  1B<  2G>
| 
| 4G<  3B>  2B<
| 
|      1G<
sdr> u turn back
|      3G<
| 
| 4B<  1B>  2G<
| 
| 4G>  3B<  2B>
| 
|      1G>
sdr> roll
|      3G^
| 
| 4B^  1Bv  2G^
| 
| 4Gv  3B^  2Bv
| 
|      1Gv
sdr> /exit