MOF14 — Minor changes to some Reflective operations

The RefAssociation ops that are parameterised by Link would be easier to
use if parameterized by two RefObjects. The RefObject ops for
add/modify/removing
ele,emts of Attribute/Reference collections should be renamed; i.e. add_value
becomes add_member. Other minor tweaks would make the interfaces easier to
use.

Discussion:

This topic was discussed by MOF RTF 1.3, but never raised as a formal issue.
The previous outcome was to defer this to the MOF 2.0 RFP.