Merge pull request #1655 from longjon/softmax-loss-todo

Move softmax loss GPU todo comment from .cu file to header file
remove SoftmaxLossLayer CPU_ONLY stubs, since there is no GPU version
Merge pull request #1656 from longjon/fix-softmax-loss-stubs

Fix an error made in removing the SoftmaxLossLayer GPU stubs
add missing value support to SoftmaxLossLayer
add spatial normalization option to SoftmaxLossLayer

With missing values (and batches of varying spatial dimension),
normalizing each batch across instances can inappropriately give
different instances different weights, so we give the option of simply
normalizing by the batch size instead.
add "make pytest" for running Python tests
[travis] remove unneeded Makefile.config sed hacking

Make allows variable redefinition, so sed brittleness can be avoided.
[travis] run pytest
initialize solver iter to zero (previously uninitialized)
[pycaffe] basic, partial testing of Net and SGDSolver
Merge pull request #1639 from longjon/crop-layer

Crop layer for automatically aligning computations
Merge pull request #1313 from shelhamer/reshape-data-layer

Reshape single input batches for inputs of varying dimension
Merge pull request #1654 from longjon/softmax-missing-values

Add missing value support to SoftmaxLossLayer
Merge pull request #1473 from longjon/pytest

Python testing
add creation script
update readme