Make Some constructor visible

[peter-tackage]

Make Some constructor visible

[tomaszpolanski]

I see one issue:
If we get a value from outside of kotlin, for example, String!, this thing would allow to be passed to Some. In that case, we would have some with possible null

[peter-tackage]

True. The question then becomes, if we can't trust the calling code to use T! appropriately (that is; treat it as T?), could we trust them to use optionOf if that was the only creator method available?

[peter-tackage]

If the Some constructor is exposed, only the initial creation will be unsafe for T! - Kotlin fails fast if you attempt to use a null value for T : Any.

[tomaszpolanski]

The reason why I like optionOf being the only way to create Some is that we are sure that it will never have inconsistent state. And people will be using those options mainly with stuff that comes from the system (T!)

[peter-tackage]

With the current: internal constructor we can still use Some("abc"), so we aren't forced to use optionOf for tests (at least in OptionTest)

[peter-tackage]

I'm going to leave it out of the API, but update OptionTest to use it.