Excelx hyperlink r:id fix + to_csv fix for :link types = no more failing tests

I was about to start working on some enhancements, but found that the test suite wasn't passing at least on my system (Mac - Mavericks).  I made some fixes and got "bundle exec rake test" and "bundle exec rspec" to both pass without failures.  One "error" remains in test:

  1) Error:
test_bug_pfand_from_windows_phone_xlsx(TestRoo):
Encoding::CompatibilityError: incompatible encoding regexp match (US-ASCII regexp with UTF-16 string) for excelx

I left that one as-is.  Hope this helps.