[ecf-dev] update to async remote service tutorial

[Scott Lewis <slewis@xxxxxxxxxxxxx>]

Hey Folks,

I've added information to tutorial 'building your first asynchronous 
remote service' [1].  Specifically, I've added sections about using the 
new Java8/CompletableFuture support, removed, shortened and clarified 
some of what was there previously, and added links to the associated 
source code in ECF's git repo...so that people can easily import the 
relevant projects and run things for themselves.

Review and any corrections/comments/suggestions would be appreciated.

Thanks to a new ECF contributor Amit Midha for his contributions...on 
which some of this was based.

Scott

[1] 
https://wiki.eclipse.org/Tutorial:_Building_your_first_Asynchronous_OSGi_Remote_Service