Removing curl dependency

[matthieujung]

Here is an update of the code in order to remove curl dependency. So functions can be run even with no internet access. Code was also rearranged to easily create a conda package. Do do that, at least a tag is needed. I don't know if the tag that I have created in my fork will be pulled. If not, remember to create a tag named with the corresponding version number of the package.

[grst]

This would fix omnideconv/immunedeconv#91

[FPetitprez]

The original intent of relying on curl was to allow signature updating without requiring users to update the package, but signatures are unlikely to change now, so they can be integrated to the package itself as this commit suggests.

[grst]

btw, it would also be great if you could make a versioned release once this is merged. Like that we can update the bioconda recipe.

[matthieujung]

The original intent of relying on curl was to allow signature updating without requiring users to update the package, but signatures are unlikely to change now, so they can be integrated to the package itself as this commit suggests.

I'm sorry, I thought these data were final. However, I don't think this is the right way to do that, because the link indicated in the code referes to the latest version of the package and not to a specific version. In this case, a version installed at a user could lead to two different results with two executions at different point time.