Add test cases to verify "Content-Length" is set properly about vip

[jweber13]

So, for jpg's, the content length is taken directly from the image. See, req.ContentLength = fstat.Size()
in HandleUpload, that image is used to check the integrity of the file size, then passed into the processFile() method, which, in the case of a jpg, is manipulated since the image is rotated right off the bat.
Using print commands to follow the changes, the data.Length result from this action is always less than the ContentLength of the image itself before it's passed through.

If what we're looking to do is test that this change is consistent, I'll need to establish assert statements in test cases, two of which I've set up (for jpg's and png's, for added comparison of results)
Right now, those tests push through images of respective types. However, data.Length in HandleUpload doesn't seem to get passed back, I'll need to find a way to retrieve that.

[foresmac]

Closed via #74