Dotnet support

[lawrence-laz]

Hi,

Great little library you have here! 👍

I wanted to use this in dotnet, but couldn't find any implementations, so I ported this myself under tinn-dotnet.

What's in it:

• All features from C ported to dotnet.
• Two-way compatibility with .tinn files.
• There is an example with MNIST database.
• There are automated tests for saving/loading and training a simple XOR network.

Hopefully some one will find this useful as well. 🙂

Also, I raised a PR #27 to add a link to this port in readme port section.

Have a great day!