Pronto is hosted on GitHub, but the easiest way to install it is to download the latest release from its PyPi repository. It will install all dependencies of Pronto and then install the pronto module:
pip install pronto
conda install -c bioconda pronto
If, for any reason, you prefer to download the library from GitHub, you can clone the repository and install the repository by running (with the admin rights):
pip install https://github.com/althonos/pronto/archive/master.zip
Keep in mind this will install the development version of the library, so not everything may work as expected compared to a versioned release.
If you do not have pip installed (the Makefile uses pip to install dependencies and then install pronto), you can do the following (after having properly installed all the dependencies):
git clone https://github.com/althonos/pronto cd pronto python setup.py install