Add ability to pass options to isInt() and toInt()

[theartoflogic]

This PR adds the ability to pass options to both the isInt() and toInt() functions. Along with the options, you can now also pass a radix to toInt().

[coveralls]

Coverage increased (+0.2%) to 96.088% when pulling c602b0a on theartoflogic:feature/int-options into 1852a5c on RocksonZeta:master.

[theartoflogic]

I need to be able to pass in options to toInt() and isInt() to support a PR I've created for the validator library (validatorjs/validator.js#532). That PR adds the allow_leading_zeroes option to isInt(), which fixes an issue I'm having trying to validate integers that have leading zeroes.

However, even if that PR is ultimately not merged, this PR would still be valid, since there are other options already exposed in the isInt() and toInt() functions in the validator library that are not exposed in this library.

[RocksonZeta]

thanks

[theartoflogic]

Should I also update the README, or is that done when a new version is released?

[RocksonZeta]

thanks ,that's my fault