print the exception message if there's no stack trace
fix numerous parser/stringifier bugs

parser fixes:
- standalone single-character literals are parsed correctly
- function 'new' and 'this' can now have any type expression
- in record types, the key for a field type can now have any type
expression
- name expressions that contain a reserved word now include a
'reservedWord: true' property

stringifier fixes:
- the all literal ('*') is now stringified correctly
- the unknown literal ('?') is now stringified correctly
- null/undefined literals with additional properties (such as
'repeatable') are now stringified correctly