Update validate-generate script to support python3

[vyp]

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I had a (relatively brief) look to find out how to detect which version of python one's fontforge would use, but couldn't find an answer. So does it just use the system python binary?

Because if so, this might work, but if not, this is probably not the solution.

Also note I have not looked at the rest of the script or anything, and this is just a very rudimentary patch I made in 2 seconds, so I do not know if this breaks anything. But running make does work for me now, as opposed to before.

[vyp]

Sorry I screwed up here. I don't think my commit exists anymore since I force changed it. Working on a clean new pull request.

[vyp]

Okay looks like github will not allow me to create a new clean pull request for whatever reason. (And I cannot reopen this one because of the force push, the reopen button is disabled.)

Here's how I think you can get it (from your own local copy of this repository):

# Make sure you are on master.
$ git checkout master

# Create a new branch to pull into (optional, but recommended so that you can
# test the "merge-request" without it affecting your current code).
$ git checkout -b python3-support

# Get my patches:
$ git remote add vyp-pr https://github.com/vyp/fantasque-sans-1
$ git pull vyp-pr master

# If you like it, and assuming you want to merge back into your master branch.
$ git checkout master
$ git merge python3-support

# Now delete my remote:
$ git remote remove vyp-pr

# And delete the python3-support branch:
$ git branch -d python3-support

OR of course, because it's such a small basic change, you can just copy paste it and update the script yourself without going through all that. (I don't care about attribution or anything.)

[vyp]

Github fixed their issue, new clean pull request at #45.