Working directory is used as root directory instead of actual root directory

[lukoerfer]

There is a line in JacocoSourceReportFactory that relativizes the paths of the source files. It uses new File(".") as root directory, which defaults to the current working directory of the JVM process that runs Gradle. There is no guarantee that this working directory is the root of the repository or the root of the Gradle project, as for example gradlew may run the process from another directory. When this happens, the coveralls task sends the absolute file paths to Coveralls. The line should be changed to use project.rootDir instead of new File(".").