Added helper for creating symlinks, along with associated tests.
Switched boost over to helper-based symlink creation.
Switched env setup over to helper-based symlink creation.
Switched remaining scripts over to helper-based symlink creation.
Added warning about wildcard based symlink creation.
Merge pull request #51 from NASA-Tensegrity-Robotics-Toolkit/symlink_existence

Symlink existence and validity checks