Installation notes, future directions

As of June 26 2021, we added an installation script and more detailed installation instructions. Our aim is to add specific installation scripts so that most computer users can use our library (we will eventually cover popular distributions of Linux, Windows, and Macs). Many engineers in the imaging informatics community use simpleITK, but many data scientists who work with medical images are users of the pydicom library. The dicom_processing module can use either simpleITK or pydicom. Even one of these optional dependencies can potentially create conflicts depending upon the user's environment. Therefore we are planning to eventually create a code-free version that will ease use for not only biomedical engineers who work with radiology images, but also for medical doctors who may have no coding skills. There is a branch for command-line interface functions, which when complete will allow such versions to be built.