Fiddle::Pointer#to_str and Fiddle::Pointer#to_int should be removed
There are Fiddle::Pointer#tostr and toint, to be used for implicit conversion to String and Integer, respectively. I think those implicit conversion methods should be removed.
(Note that there are tos and toi, explicit conversion to String and Integer, respectively.)
About to_str: Because Fiddle::Pointer is not always a pointer of char *, and careless conversion of invalid pointer to a string would frequently cause SEGV. So, I think implicit conversion to string is very danger and it should be removed.
About toint: Unlike tostr, pointer arithmetic methods are available in Fiddle::Pointer, but it lacks many methods for treating it as integer, and I think Fiddle::Pointer is not suitable for implicit conversion to integer.