empty lists and None values as initial values in declarations.
Now, these values are accepted irrespective of the declared type. It
is up to the typechecker to validate them.
and "nothing".
Until now only products of type names were allowed: I extended
them to allow type expressions.
Removed the destructive update of a map binding "a[b] := c".
Record projection has been extended to allow for qualified
names: "a.b.c" and "a.b.c[d]".
Changed the LIGO extension from ".li" to ".ligo".
Fixed the name of the language to be "LIGO" (instead of "Ligo").
