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.
Removed the questionable Pressure Advance feature. It is better to use the Pressure Advance implemented into a firmware.
Added a C++ implementation of GCodeReader and SpiralVase, thanks to @alexrj
Added a C++ implementation of GCodeTimeEstimator, thanks to @lordofhyphens
