Sync w master: add polyline insert/drop
Cosmetic change: w_old -> old_w in ge_axis.c
Undo/redo revisited
correct bug: g_strdup => g_strdup_printf
sync pars.yacc: add TARGET POLYLINE, enhance COMPOUD
Sync with gtk3 branch for PolylineType
Cosmetic changes in Python interface
Comment croix_2_inline[] definition