0) Output of expr evaluator returns base Python elements; this seems to show a good speedup in the interpreter

1) Assertions return a exit code 255 - issue #99 resolved
2) Add support for binary operators >> and << ; right and left shifts
   Language feature and issue #98
3) Add support for unary operator bit complement ~
4) Update logical not operator to return (T) / (F) along with poi-mei in its str representation
5) Builtin str in Python is used directly in Ezhil
6) scanner symbols have to be in sequence with the
   length of token types, otherwise odd things can happen
7) use x-platform coding in Ezhil; Windows platform returns "win32" for call sys_platform()
8) updated known failure list for testing.

9) add xor operation as a Ezhil builtin function; & add unittest
10) golden ratio
11) ezhil support for Python3
12) ezhil staircase light example
13) kludge of eval builtin
14) mathipeedu