Fix for #568 isssue

Maven working fine, and I made corresponding changes to _build.gradle.

Explanation : 
liquibase.structure.core.Schema.setDefault(Boolean) is missing in liquibase-core version 3.0.8.

So I updated liquibase to version 3.2.0, but version 3.2.0 depends on "jetty-servlet" which clashed with "spring-boot-starter-tomcat". So either I can change "spring-boot-starter-tomcat" to "spring-boot-starter-jetty" or exclude "jetty-servlet".

I excluded "jetty-servlet" from "liquibase-core" in order to use tomcat as embedded server.

Maven build is working fine for me, and I think gradle build will also do.