Problem: No tests for comparing special variables. Error in jsondecode() not reported. test_json does not work Japanse system. Solution: Set scriptencoding. (Ken Takata) Add a few more tests. Add error.
Problem: type() does not work for v:true, v:none, etc. Solution: Add new type numbers.
Problem: No support for JSON. Solution: Add jsonencode() and jsondecode(). Also add v:false, v:true, v:null and v:none.
