Return None instead of raising OverflowError on an out-of-range value

[eeshsaxena]

I was feeding some messy strings through timeparse and hit a crash on a very large number:

>>> from pytimeparse import timeparse
>>> timeparse('9' * 400 + '.5 minutes')
Traceback (most recent call last):
  ...
OverflowError: cannot convert float infinity to integer

The value is syntactically fine, it is just enormous. float() on it overflows to inf, and the integer-returning branch then does int(sum(...)), which cannot convert inf and raises OverflowError.

The function already handles a malformed number field: a string like '1.2.3 seconds' throws ValueError from float(), which is caught so the parser moves on and ultimately returns None. The out-of-range case is the same situation, the field just is not a usable number, but OverflowError was not in the except, so it escaped instead of falling through to None.

The fix is to catch OverflowError alongside ValueError in that block. After it, '9' * 400 + '.5 minutes' returns None like any other input that cannot be parsed, and normal values are untouched.

I added a test for the out-of-range case and the full suite still passes (50 tests).