Fix row numbering

[leeper]

Due to how some of the response data.frames are constructed, row numbering gets weird:

> x <- SearchQualificationTypes()
6 of 6 QualificationTypes Retrieved
> x
              QualificationTypeId         CreationTime                              Name
2  3UYIJTD339RDC0B6ZY4U566J8D3I3R 2015-04-11T19:03:59Z                    A12QUZGOA8ZLFY
21 33MAVWP2GR8GNUQ558WG1N3Q4CHLZQ 2015-01-05T10:15:09Z            Completed Previous HIT
3  35DYG1NTFVLY52OF3F0K42PKZFO6M4 2016-02-10T16:38:54Z  Completed Related Headline Study
4  27UQ6SVQ8H8859LLY8FB1CI1R0VO5O 2012-12-20T22:43:11Z                  Study Completion
5  22HK2JE1M7PK3SC699FZGC04L3MWPN 2013-11-05T06:56:42Z           Temporary Qualification
6  3SRUE8JDW5TQM19DBC5S400PYI9O5Y 2014-10-16T14:38:27Z Three-Question Qualification Test

This requires:

• Manually setting the rownames attribute as a sequence (since these are meaningless anyway)
• While I'm at it, check the use of stringsAsFactors
• And make sure empty data.frames are returning character class columns