Fix Sonar execution

See merge request pdsl/cbc4j!2

Develop/patrik/gitlab cicd

See merge request pdsl/cbc4j!1

Modification of developer connection to add common

-Dproject.scm.developerConnection=scm:git:http://git.patrikdufresne.com/common/cbc4j.git
would not work in Jenkins.

Added common to the path of developerConnection

To avoid multiple call to get the best solution of the linear problem,
add a method to return a double[].

Update gitignore.