UPM 2048 and opsz axis (#462)

- UPM is adjusted to 2048
- Additional opsz VF axis (multi master) added which will eventually replace the separate Display family
- New tooling that uses fontmake instead of Inter's own fontbuild toolchain. (The old toolchain is still supported, i.e. `make -f Makefile_v1.make ...`)

misc/tools/subset-designspace.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+import sys, os
+from os.path import dirname, basename, abspath, relpath, join as pjoin
+from fontTools.designspaceLib import DesignSpaceDocument
+
+
+def subset_designspace(designspace, filename):
+  italic = filename.find('italic') != -1
+
+  rmlist = []
+  for a in designspace.axes:
+    if a.tag == "slnt" or a.tag == "ital" or a.tag == "opsz":
+      rmlist.append(a)
+  for a in rmlist:
+    designspace.axes.remove(a)
+
+  rmlist = []
+  hasDefault = not italic
+  for source in designspace.sources:
+    isitalic = source.name.find('Italic') != -1
+    if italic != isitalic or source.name.endswith('Display') or source.name.endswith('opsz'):
+      rmlist.append(source)
+    elif italic and not hasDefault:
+      source.copyLib = True
+      source.copyInfo = True
+      source.copyGroups = True
+      source.copyFeatures = True
+      hasDefault = True
+  for source in rmlist:
+    designspace.sources.remove(source)
+
+  rmlist = []
+  for instance in designspace.instances:
+    isitalic = instance.name.find('Italic') != -1
+    if italic != isitalic:
+      rmlist.append(instance)
+  for instance in rmlist:
+    designspace.instances.remove(instance)
+
+  print("write %s" % relpath(filename, os.getcwd()))
+  designspace.write(filename)
+
+
+def main(argv):
+  src_designspace_file = argv[1]
+  dst_designspace_file = argv[2]
+  designspace = DesignSpaceDocument.fromfile(src_designspace_file)
+  designspace.lib.clear()
+  subset_designspace(designspace, dst_designspace_file)
+
+
+if __name__ == '__main__':
+  main(sys.argv)