Importing String support changes

[sohah]

There has been work on supporting String in SPF in two GSoC projects. The most recent link to this work is here. Since the work is not directly pulled to our repo, we can perhaps move that work manually to SPF's repo.

@yannicnoller , can we start by making a new branch for SPF for string support, where we can cherry pick some of the commits from these changes. Another direction is to follow up with the owner of this repo and to give us admin access to make the necessary changes until we import the changes on SPF's main repo

[yannicnoller]

Hi @sohah, sure sounds good! Let me know how I should assist!