Removed downsample.txt

doc/library/tensor/signal/downsample.txt

-.. _libdoc_tensor_signal_downsample:
-
-======================================================
-:mod:`downsample` -- Down-Sampling
-======================================================
-
-.. module:: downsample
-   :platform: Unix, Windows
-   :synopsis: ops for performing various forms of downsampling
-.. moduleauthor:: LISA
-
-.. seealso:: :func:`theano.tensor.nnet.neighbours.images2neibs`
-
-.. function:: fft(*todo)
-
-    [James has some code for this, but hasn't gotten it into the source tree yet.]
-