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 ...`)

init.sh

@@ -316,6 +316,7 @@ else
   fi
 
 
+  # note: ttfautohint is no longer used by the new Makefile
   AUTOHINT_VERSION=1.8.2
   AUTOHINT_SRC_VERSION=1.8.2.8
   LINK=false