4.23. bltk

Prior to this update, the bltk tree was corrupted. As a result, the bltk_report script failed. This update modifies the settings of the bltk root path. Now, the report script works as expected.

Prior to this update, bltk could be installed without requiring the gnuplot binary. As a result, the bltk_plot script exited with an error message when the gnuplot package was not installed and the charts were shown from measured data. This update requires the gnuplot package for its installation. Now, the bltk_plot script no longer exits with an error.