Update scripts for current fontforge

[rstub]

The syntax of AddAnchorClass has changed, c.f. http://fontforge.10959.n7.nabble.com/New-AddAnchorClass-syntax-td11063.html

For reference:

• http://fontforge.github.io/en-US/documentation/interface/lookups/
• https://fontforge.github.io/scripting-alpha.html#A

[rstub]

Updated links:

• https://fontforge-users.narkive.com/CpW0A3oP/new-addanchorclass-syntax
• https://sourceforge.net/p/fontforge/mailman/fontforge-users/thread/20080522030253.196716ys41onu1ms%40web.mail.umich.edu/
• https://fontforge.org/docs/ui/dialogs/lookups.html
• https://fontforge.org/docs/scripting/scripting-alpha.html