1.42-alpha4.0 : auto purge block.

new

• purge block volume now can be automatically computed. You have to set the "filament pigment" setting (how hard it is to clear the nozzle) and the different settings in ""hardware settings" -> single extruder mm setup" -> "advanced wipe". The purge block values are printed on the terminal. #30

bug fix

• #24 #31 #32 #33

issues

• overlap & ironing are broken. Will be fixed in the next release.