* refactor Infill rotation template
* clean up comments
* set default solid_infill_rotate_template to empty
* Fix an issue that infill_direction solid_infill_direction not working as expected
* Add Extra Solid Infill Feature
Introduced a new feature to insert extra solid infills at specific layers for enhanced strength in 3D prints.
* fix doc error
* fix image name
* support "#K" for Explicit Layer List
* update wiki
