Adapt MNIST example to use the original lecun data files

[jrp2014]

This version downloads and uses the MNIST data files, converting the data from Word8 to Double. The runMNIST.sh script does the work.

Unfortunately, it still runs out of memory on my Ubuntu VM...

Anyway, I hope that it's of some use.

[jrp2014]

The CI seems to confirm that it's not just an issue with my setup.

[erikd]

The Data.Semigroup import needs to be wrapped in some CPP goop.

Let me do that in a separate PR.

[erikd]

I am actually wondering why we don't just update the documentation.

[erikd]

For PR branches like this one, you really should rebase rather than merge,

[jrp2014]

The CI fails because gan-mnist takes too long to generate 15 examples. mnist itself still uses too much memory to run.

[erikd]

Where is this this PR going? If this is ever to be merged it should be rebased against master and commits like "ci typo" need to be squashed down.

[jrp2014]

Thanks @erikd. I want to find time over the w/e to kick the tyres some more:

• better run script (so that args can be passed)
• use that to limit travis.yaml test runs so that they pass within time and space constraints
• improve formatting / intelligibility of output
• try some different example models in mnist
• a couple of lines of documentation on how to run, easily
• optimization (eg, by profiling) for time / space improvements
• git hygiene

Are you going to be able to refactor the script?

[erikd]

Probably best if I wait until you finish what you are working on and then assuming everything is ok, I will do done final clean up run