Properly accept 0 as a value for connectTimeout and loginTimeout
Set default connectTimeout to 0

This in effect preserves the previous behavior where we would
set SQL_ATTR_LOGIN_TIMEOUT to 5. It seems that setting a timeout
value for SQL_ATTR_CONNECTION_TIMEOUT causes an assertion error
with the FreeTDS driver
Use SQLUINTEGER for connectTimeout and loginTimeout

Before we were using plain int. This is just an attempt to be accurate
in hopes of fixing a FreeTDS assertion when connecting with a value for
connectTimeout