Splitting the convolution layers. (#448)

* Splitting the convoltion layers.

* Fixing the import of densenet.

* Fixed pep8

Author: gabrieldemarmiesse

keras_contrib/applications/densenet.py

@@ -72,7 +72,7 @@
 from keras.applications.imagenet_utils import preprocess_input as _preprocess_input
 import keras.backend as K
 
-from keras_contrib.layers.convolutional import SubPixelUpscaling
+from keras_contrib.layers import SubPixelUpscaling
 
 DENSENET_121_WEIGHTS_PATH = (r'https://github.com/titu1994/DenseNet/releases/download'
                              r'/v3.0/DenseNet-BC-121-32.h5')

keras_contrib/layers/__init__.py

@@ -5,8 +5,9 @@
 from .advanced_activations.swish import Swish
 from .advanced_activations.sinerelu import SineReLU
 
-from .convolutional import CosineConv2D
-from .convolutional import SubPixelUpscaling
+from .convolutional.cosineconvolution2d import CosineConv2D
+from .convolutional.cosineconvolution2d import CosineConvolution2D
+from .convolutional.subpixelupscaling import SubPixelUpscaling
 
 from .core import CosineDense