DH 4: ref+fix: simpler bool check, including 'undefined'

[coolaj86]

Cleaner, easier to read and understand, also handles the case of undefined, rather than throwing an error.

Also corrects the type of getRawTransaction in a backwards-compatible way:

• arg > 0 preserves the truthiness of values previously marked as int, providing an upgrade path

Should undefined throw?

If throwing an error for undefined is actually the desired behavior, this change can be made:

- return (String(arg).toLowerCase() === 'true' || arg > 0);
+ return (arg.toString().toLowerCase() === 'true' || arg > 0);