Positioning needs to be reset for path's M.

Path's 'M' indicates absolute positioning. The position of the previous_element--or even whether there was a previous element--is irrelevant. 

(Side note: the `if (previous_element == null)` that this pull request removes always evaluates to false because previous_element is assigned to around line 292. `if (previous_element.element == null)` is probably what was intended.)