added xml encoding header with etree
added quick example with blend file and svg output
added a workaround to prettify the SVG output with etree
added a note in README about the needed blender version
added a new module called visivle_advanced that can render the visible edges in SVG with color and thickness according to values passed by freestyle shaders, allowing to achieve more complex effects. Made hardcoded values for color and thickness in other modules easier to edit by the user
typo