Start publishing ReadTools versions in maven central

[magicDGS]

This will allow to use ReadTools in downstream toolkits and have them backup there instead of relying only on GitHub releases. We should also make the process automatic by using gradle/scripts/travis.

[magicDGS]

I have already setup the maven coordinates for com.github.magicdgs: https://issues.sonatype.org/browse/OSSRH-42322?jql=

[magicDGS]

I guess that this cannot be done until we have use released dependencies in Maven central (requies probably #443)

[magicDGS]

We can actually setup releases since 1.4.0, as we have the dependency in our custom patch from https://github.com/bioinformagik/gatk that we can try to publish in maven central.