fix: chart appears with 0 font size if option value is not set in the config
fixes working dir issue in the launcher script
fixes issue #1018
fixes task hierarchy broken in the previous changeset
#version GP 2.7-r1817
Added tag ganttproject-2.7-betaIV for changeset 3ce55fcb2343
Merge with c8a49fc3bfbae79d75ac7b2f5d748373acaa3c14
#version 2.7-betaIV-r1820