Modify parsing exceptions (errors when parsing non-uniform substrings of null values)

[jiushill]

I met a problem in parsing.

  File "C:\Program Files\Python37\lib\site-packages\Evtx\Nodes.py", line 1555, in string
    raise ParseException("Error parsing uneven substring of NULLs")
Evtx.BinaryParser.ParseException: Parse Exception(Error parsing uneven substring of NULLs)

I tracked down 1555 lines of Nodes.py and found that rasie caused the termination of the whole program.

I tracked Nodes.py's 1555 lines and changed it to pass to solve the problem.