Need to document how to checkout git submodules.

[samuelcomeau6]

When the repo is cloned, it does not copy the other repositories. You seem to have them somehow linked in the repository so they display correctly on github, but when you actually clone them, they are empty folders. If there is a special way to do this correctly it HAS to be in the documentation.

They are git submodules. There’s a nice tutorial here: https://gist.github.com/gitaarik/8735255. I’ll be updating this issue when the documentation is updated.

I've updated the README.md to include instructions to clone the submodules as well as a link to a document describing what git submodules are: https://github.com/tinyfpga/TinyFPGA-Programmer-Application/blob/master/README.md