First commit of module for molecular crystalline order from Jake McKi…

…bbin, Erik Santiso and me

This module will provide tools for comparing the relative orientations of molecules in a medium with the
orientations that they have in the ideal crystal structure of the solid.  Some of the functionality for
this sort of CV is already available in PLUMED.  Tests to ensure that you can use these features in the way
that Jake and Erik use them have thus been included in this commit.  This commit also includes the beginnings
of a class for calculating quaternions.  This class will be used when determining the orientations of the molecules.

regtest/.gitignore

@@ -10,6 +10,7 @@
 !/basic
 !/core
 !/crystallization
+!/crystdistrib
 !/dimred
 !/eds
 !/drr

regtest/crystdistrib/Makefile

@@ -0,0 +1,2 @@
+include ../scripts/module.make
+

regtest/crystdistrib/rt-dops-forces/Makefile

@@ -0,0 +1 @@
+include ../../scripts/test.make

regtest/crystdistrib/rt-dops-forces/colvar.reference

@@ -0,0 +1,4 @@
+#! FIELDS time opf0 opf1 opf2 opf3 opf4 opf5 opf6 opf7
+ 0.000000   6.9433  27.6362  14.9697  36.8257  11.3430  39.2925  19.4209  38.2635
+ 0.025000   8.2701  25.1047  14.9222  35.9648   9.7691  37.7001  20.6153  38.1927
+ 0.050000   9.8357  21.1581  14.1746  34.0344   8.7656  37.5896  17.8528  37.5282