Use more than 255 characters for TEXT columns.

We are using the library to fetch long text data from columns with text datatypes. We needed to manually set the TEXTSIZE, as there is a bug in Microsofts text field implementation as documented here:
http://www.freetds.org/userguide/troubleshooting.htm

Anyhow, in order to make this work, SYBTEXT types should not be truncated to size 255. I hope this is how it should work in general, therefor we created this pull request. 

Also, we use it on OSX as target and not iOS, which works just fine for us. So it wouldb be great if the podspec would include OSX as a target. :)

br
denis