Tracking issue: optimisation panel improvements

[abey79]

•  Feat: add support for line merge optimisation #126
•  Feat: add support for reloop optimization #127
•  Feat: add support for line simplify optimization #128
•  Line sort should have an option to split compound paths #123
• expose tolerances and other parameters
• add option to apply optimization on the rendered file as well
• Line sort optimization appears to be broken #130