[transfer-engine] Rotate image to the right orientation after scaling.

When scaling an image it actually destroys the metadata because Qt doesn't know
anything about it. Before we have a proper metadata handling interface, let's just
rotate image to the right orientation.

TODO: Write exiv2 based metadata handling.
Fixed and updated unit tests
Review fixes
Merge pull request #13 from zchydem/master

[transfer-engine] Rotate image to the right orientation after scaling.