perglue.cpp - use static_cast instead of dynamic_cast if possible,

use switch instead of plenty of ifs,
export clone<DynamicPrintConfig> to Perl XS.

xs/xsp/my.map

@@ -31,6 +31,7 @@ Clone<BoundingBoxf3>       O_OBJECT_SLIC3R_T
 
 DynamicPrintConfig*        O_OBJECT_SLIC3R
 Ref<DynamicPrintConfig>    O_OBJECT_SLIC3R_T
+Clone<DynamicPrintConfig>  O_OBJECT_SLIC3R_T
 
 StaticPrintConfig*         O_OBJECT_SLIC3R
 Ref<StaticPrintConfig>     O_OBJECT_SLIC3R_T

xs/xsp/typemap.xspt

@@ -39,6 +39,7 @@
 %typemap{Clone<BoundingBoxf3>}{simple};
 %typemap{DynamicPrintConfig*};
 %typemap{Ref<DynamicPrintConfig>}{simple};
+%typemap{Clone<DynamicPrintConfig>}{simple};
 %typemap{StaticPrintConfig*};
 %typemap{Ref<StaticPrintConfig>}{simple};
 %typemap{PrintObjectConfig*};