Vulnerable dependencies in POM

[mattebit]

This is on the api branch commit e276dba

<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-server</artifactId>
    <version>9.4.3.v20170317</version>
</dependency>
<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-servlet</artifactId>
    <version>9.4.3.v20170317</version>
</dependency>
<dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-crypto</artifactId>
    <version>5.4.6</version>
</dependency>

Update to latest version and fix dependent code if necessary

[simone36050]

A solution is provided in #18.