contact export when merging households: some household fields missing

1) setup the following records:

• Individual A (household member of Household 1)
• Individual B (household member of Household 1)
• Household 1

2) search for and select the two Indiv contacts

3) export and use the merge to household option

Result: the two indivs are merged into the single household record. however, certain data in key fields are missing from the export, including the addressee field and state_province

Comment: it doesn't look like anything too significant changed in Export/BAO/Export.php with regard to the relationship field behavior between v4.2 and v4.3, so I suspect the problem was introduced due to changes higher up in the code – possibly with some of the pseudoconstant changes affecting the DAO layer. with the two examples above, the problem is that the array keys in the export object do not match the array keys in the field mapping. for example, state_province vs. state_province_id, and addressee vs. addressee_display.

I'll submit a PR that addresses these two issues, but I think that we should review how that entire chunk of code is handled, as there are likely other problems present.