perform simple data sanitization

[crobinson42]

When calling send(...) with an email address that has whitespace ie: myname@gmail.com this error is returned:

... [ { message: 'At least one valid recipient is required', code: 5002 } ],statusCode: 400 } ...

This can go both ways as far as whos's responsibility it is but it would be nice if the node-sparkpost pkg (or even the sparkpost backend) handled simple data sanitization's.

[crobinson42]

node-sparkpost npm pkg 2.1.4