Build Infrastructure update: maven profile to publish distribution on S3 

Two issues addressed:

 - maven assembly plugin _assembly:assembly_ goal is deprecated and considered a bad practice so i implemented _assembly:single_ one instead as [books recommend us](http://books.sonatype.com/mvnref-book/reference/assemblies-sect-controlling-contents.html)
   Took A LOT of time but at the end: ```mvn package -P build-distr``` assembles the distribution

 - ```mvn package -P upload-distr``` assembles distribution and uploads it to s3://zeppel.in (if AWS access key is confgured)

Needs to be tested more before merging.