Adopt line spec for Instruments spec

[dave.wolfe]

The insertion routines should recognize specs made from the custom parts spec or the placeholder spec and allow components placed from those specs to adopt the spec of the line they are on.

Right now, if the spec is not named custom parts or placeholder, the program will try to find connecting components like flanges in the current spec and not the spec of the line the item is being placed on.  For example, I created an instruments spec to hold control valves, but when a valve is placed, flanges are not found in the instrument spec.

The ContentType property from the Repository Desriptor field can be used to see whether to allow adopting the spec when placed or not.