faq.rst: Add section: no rows with new FreeTDS

Describes this issue: https://github.com/pymssql/pymssql/issues/137

And how upgrading to pymssql 2.x or 1.0.3 fixes the problem.
faq.rst: Minor formatting tweak; single to double backquotes
Merge pull request #175 from pymssql/docs_faq_no_results

Add section to docs describing issue where old pymssql versions return no rows when used with new FreeTDS versions