Merge branch 'LocalParamQuat_template' into 'master'

to discuss : made LocalParametrizationQuaternion template & use partial specialization

Since `LocalParametrizationQuaternion` private member `delta_reference_` is set at instantiation, does not change and is used to specialize computation it is better to use a template partial specialization scheme.

If having the empty template bracket when using the default value `DQ_GLOBAL` is a killer, we can always consider typedef.

See merge request !83