Reverted back to SBT for dependency management;
Figured out that Disruptor can hardly be used for any callback due to missing relation between issued event and event-processing. Disruptor code will soon be removed,

Reason:
In simple words, whatever you put in a ring-buffer gets processed but linking the result back
to the initiating invocation is not possible because there is
connection between an event's result and the emitting event invocation.
However, what you can and should do for asyn processing is
pushing the final result into a second output buffer and then
use an eventHandler for sending the result back to the caller.
This requires, for instance, an http or websocket handler
holding a session ID. Through the session ID, the http handler can eventually send the result back to the right client.

However, for IPC and in particular for async processing
this would require generating an UUID for each caller in order to match the actual event result back to the callee but this overhead almost nullifies the purpose of a ring-buffer.
Removed a bunch of old lib Jar files.
Removed some old Sandbox files.
Add a performance tweak to SimilarityCalculator that brings
variance down. Read comment for details.