Add RxJava 3 extensions (#33)

Hide component1() destructuring from Java consumers (#30)

I propose simple change that i think would be beneficial from the perspective of java consumers, namely annotating `component1()` function with kotlin's `@JvmSynthetic`

As a consequence method will become invisible from Java. Long story short i think it's rather unneccesary to pollute java with a method that quite frankly doesn't say anything for them as the concept of kotlin's destructuring is simply not there. For getting actual values there is `toNullable` already so i don't see a point

Right now it looks like this:

![koptional-in-java](https://user-images.githubusercontent.com/2744747/43391846-106b5ac8-93f2-11e8-9701-5f9d6940eef8.png)

Destructuring refinements. (#26)

Addresses remaining feedback of PR #20.

Update Kotlin 1.1.1 → 1.2.41. (#23)

* Update Kotlin 1.1.1 → 1.2.41.

* jvmTarget 1.8 for reactor tests.

Split usage samples in README into sections. (#15)

Add filterSome and filterNone extensions for Flowable, Maybe and Sing…

…le. (#12)

Add explanation behind absence of functions like map(), getOrElse(). (#6

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Add RxJava2 extensions for Observable. (#2)