Updated doc to move gpuarray out of sandbox

doc/library/sandbox/gpuarray/dnn.txt

 .. _libdoc_gpuarray_dnn:
 
 ===========================================
-:mod:`theano.sandbox.gpuarray.dnn` -- cuDNN
+:mod:`gpuarray.dnn` -- cuDNN
 ===========================================
 
 .. moduleauthor:: LISA

doc/library/sandbox/gpuarray/index.txt

@@ -2,7 +2,7 @@
 .. _libdoc_gpuarray:
 
 =======================================================
-:mod:`theano.sandbox.gpuarray` -- The (new) GPU backend
+:mod:`gpuarray` -- The (new) GPU backend
 =======================================================
 
 .. module:: theano.sandbox.gpuarray

doc/library/sandbox/gpuarray/type.txt

 .. _libdoc_gpuarray_type:
 
 ===================================================
-:mod:`theano.sandbox.gpuarray.type` -- Type classes
+:mod:`gpuarray.type` -- Type classes
 ===================================================
 
 .. automodule:: theano.sandbox.gpuarray.type

doc/library/sandbox/index.txt

@@ -14,7 +14,6 @@
     :maxdepth: 1
 
     cuda/index
-    gpuarray/index
     linalg
     neighbours
     rng_mrg

doc/tutorial/using_gpu.txt

@@ -393,7 +393,7 @@ into a file and run it.
 
 .. testcode::
 
-  from theano import function, config, shared, tensor, sandbox
+  from theano import function, config, shared, tensor
   import numpy
   import time
 
@@ -461,7 +461,7 @@ the GPU object directly.  The following code is modifed to do just that.
 
 .. testcode::
 
-  from theano import function, config, shared, tensor, sandbox
+  from theano import function, config, shared, tensor, gpuarray
   import numpy
   import time
 
@@ -470,7 +470,7 @@ the GPU object directly.  The following code is modifed to do just that.
 
   rng = numpy.random.RandomState(22)
   x = shared(numpy.asarray(rng.rand(vlen), config.floatX))
-  f = function([], sandbox.gpuarray.basic_ops.gpu_from_host(tensor.exp(x)))
+  f = function([], sandbox.gpuarray.basic_ops.GpuFromHost(None)(tensor.exp(x)))
   print(f.maker.fgraph.toposort())
   t0 = time.time()
   for i in range(iters):
@@ -485,9 +485,10 @@ the GPU object directly.  The following code is modifed to do just that.
   else:
       print('Used the gpu')
 
-Here the :func:`theano.sandbox.gpuarray.basic.gpu_from_host` call
-means "copy input to the GPU".  However during the optimization phase,
-since the result will already be on th gpu, it will be removed.  It is
+Here the :func:`theano.sandbox.gpuarray.basic_ops.GpuFromHost(None)` call
+means "copy input to the GPU", with ``None`` the default GPU context when not
+explicitly given. However during the optimization phase,
+since the result will already be on the gpu, it will be removed.  It is
 used here to tell theano that we want the result on the GPU.
 
 The output is