Breakpoint in callback teminates node (#62)

Fix for issue #62 where placing a breakpoint in the callback of any
node-sqlserver functions (such as sql.query(..)) caused node to
terminate.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/WindowsAzure/node-sqlserver
Merged with upstream master https://github.com/WindowsAzure/node-sqlserver
Merge branch 'master' of https://github.com/clintwood/node-sqlserver