VirtMat kernel should be available from any directory

As indicated in issue #148 (closed), use of the VirtMat kernel is currently limited to the MySampleDir/vre-language/virtmat_kernel directory.

For optimal flexibility, and usability, the kernel should not be "locked" to one directory, but rather available in any path the user's project(s) might require. Thus, the installation method of the kernel should be reviewed.