message: Rename Table keytype to keytypes (plural)
  Fixes transaction error when loading Abi and contract.
diff: @@ -66,7 +66,7 @@ struct Table
  table Name # the name of the table
  indextype TypeName # the kind of index, i64, i128i128, etc
  keynames TypeName[] # names for the keys defined by keytype
  - keytype TypeName[] # the meaning / type of key parameters, how to convert binary key to json
  + keytypes TypeName[] # the meaning / type of key parameters, how to convert binary key to json
  type TypeName # the meaning / type of the binary data stored in this table
  struct Abi
  