Optimization of the configuration layer:

The values of StaticPrintConfig derived objects were searched by a name
walking through a huge chained if.
Now they are being mapped with a std::map.
Also initialization of StaticPrintConfig classes from their ConfigOptionDef
defaults is done by maintaining a single global definition of each
StaticPrintConfig derived class, and a new instance is initialized
from this static copy.

Also the ConfigOption instances are casted using static_cast
wherever possible, and their types are verified by a virtual type() method.
This approach avoids insiginificant performance penalty of a dynamic_cast.

Also the compare and clone methods were added to ConfigOption,
and the cloning & compare work on binary values, not by serialization.

xs/src/libslic3r/PlaceholderParser.cpp

@@ -64,7 +64,7 @@ void PlaceholderParser::update_timestamp()
 void PlaceholderParser::apply_config(const DynamicPrintConfig &config)
 {
     for (const t_config_option_key &opt_key : config.keys()) {
-        const ConfigOptionDef* def = config.def->get(opt_key);
+        const ConfigOptionDef* def = config.def()->get(opt_key);
         if (def->multiline || opt_key == "post_process")
             continue;