Bug in rotate

[RainerHeintzmann]

Just noticed that the rotate function has a bug, at if run on images with unequal sizes.

using IndexFunArrays, FourierTools
b = box((901,1178), (700,1000))
rotate(b, 20.0)

leads to a strangely distorted result. The former right angles are not right angles any more.
If you rotate by 45 degrees, the former rectangle becomes a square.
There are also some wrap-around problems due to the shear operations, which should be removed.