Prepare examples.md

[pivovarit]

[cvgaviao]

I'm in a need for such resource.
I'm migrating to java8/11 from 6 and would love to see examples of how to use CompletableFutures with your ThrowingSupplier. Could you point me to any ?

[pivovarit]

@cvgaviao I totally missed that comment - I will tackle this issue by myself, and some examples should pop up in README soon.