addressee/postal/mailing greeting -- clean string on construction

the attached patch improves the construction of addressee, postal, and email greeting fields by removing leading, trailing, and double spaces.
the current behavior is prone to leaving extra spaces, especially for individual contacts (e.g. if the middle name is part of the formula but the contact does not have data in that field).

note – the stripSpaces function may be better off moved to the BAO or DAO file for general access. i couldn't find any existing functions that served this purpose.