Refactored setting permissions when rezzing items: use the same function when rezzing from user inventory and prim inventory.

Also, fixed a bug: when rezzing a coalesced object from a prim's inventory, apply the coalesced object's name and description only to the first sub-object; not to all the objects in the coalescence. (This was already done correctly when rezzing from a user's inventory.)
Refactored: use a single function to apply an object's folded permissions to its main permissions
When creating a coalesced object, set its Creator ID if all the objects have the same creator
When creating a coalesced object, set its permissions to the lowest-common-denominator of all the sub-objects
Merge branch 'justincc-master'