updated the regtest for ABMD

regtest/rt14/COLVAR.reference

-#! FIELDS time rmsd abmd.bias
- 0.000000  3.966 82.163
- 0.050000  3.970 83.104
- 0.100000  3.973 83.757
- 0.150000  3.977 84.673
- 0.200000  3.982 85.838
+#! FIELDS time rmsd abmd.bias abmd.min_1
+ 0.000000  3.966  0.000 15.732
+ 0.050000  3.970  3.632 15.162
+ 0.100000  3.973  7.469 14.923
+ 0.150000  3.977 11.497 14.747
+ 0.200000  3.982  7.695 14.982

regtest/rt14/plumed.dat

 RMSD LABEL=rmsd REFERENCE=reference.pdb TYPE=SIMPLE
 
-ABMD ARG=rmsd KAPPA=20 MIN=1.0 TO=2.0 LABEL=abmd
+ABMD ARG=rmsd KAPPA=20 TO=0.0 SEED=12 NOISE=0.2 LABEL=abmd
 
 PRINT ...
   STRIDE=1
-  ARG=rmsd,abmd.bias 
+  ARG=rmsd,abmd.bias,abmd.min_1 
   FILE=COLVAR FMT=%6.3f
 ... PRINT