Overwrite the default behaviours of Hash::Merge with merging only bet…
Created by: Zhicheng-Liu
…ween hashes
With the default behaviours (LEFT_PRECEDENT) of Hash::Merge as described at http://search.cpan.org/~rehsack/Hash-Merge-0.200/lib/Hash/Merge.pm#BUILT-IN_BEHAVIORS, it is difficult on the plugin side to overwrite the configuration items with array values.
Related to ENSEMBL-4767.