Add option for external pull potential
An module other than the pull code can now provide the potential
and force for a pull coordinate, when the pull coordinate type is set
to external-potential. It is the responsibility of the module to call
a function that applies the scalar force to the atom in the groups
involved in th pull coordinate. A registering function has to be
called by the provider module at setup. This function checks the
consistency of the pull setup and checks a provider string the user
provided against the string of the providing module.
This functionality is intended to be used by the AWH module.
Removed the set_pull_coord_reference_value() function. Instead of
externally modifying the reference value, an external pull potential
should be used.
Change-Id: I231fe43fe3a2148a7a77d979b0fdb234d3de5c9b
12 files changed: