Newline is not default

[uyw4687]

Many java projects have one newline after the copyright statement, however, license-maven-plugin doesn't support this feature.
Simple hack is possible by adding newline to endLine but this doesn't ensure just 'one' newline is added since the plugin just adds in the position, not checking the newline.

mathieucarbou/license-maven-plugin#78

[uyw4687]

However this problem is not fatal since we can override the setting as follows

    license {
        headerDefinitions.add(
                HeaderDefinitionBuilder.headerDefinition("slashstar_style")
                        .withFirstLine("/*")
                        .withBeforeEachLine(" * ")
                        .withEndLine(" */\n")
                        .withAfterEachLine("")
                        .withSkipLinePattern(null)
                        .withFirstLineDetectionDetectionPattern("(\\s|\\t)*/\\*.*\$")
                        .withLastLineDetectionDetectionPattern(".*\\*/(\\s|\\t)*\$")
                        .multiline()
        )
    }

and the previous false newlines are overridden by new application(when the previous statement becomes old when the new year comes.)

[uyw4687]

cc @minwoox

[uyw4687]

created a PR mathieucarbou/license-maven-plugin#629