Add oversampling and gaussian filter to hollowing.

* Additional steps hollowing and drilling in SPAPrint
* Remove SLABoilerPlate.hpp as it was empty.

src/libslic3r/SLA/SLACommon.hpp

@@ -3,6 +3,8 @@
 
 #include <memory>
 #include <vector>
+#include <numeric>
+#include <functional>
 #include <Eigen/Geometry>
 
 #include "SLASpatIndex.hpp"