Implemented serialization and deserialization of models in symbol fields
through the SIM_VALUE class. We don't carry the Spice legacy of
case-insensitive suffixes, instead we conform to the SI standard (i.e. M
is Mega, not milli, P is peta, p is pico).
Parameter grid value validation is implemented by simply not allowing
any characters that will make the value invalid (instead of highlighting
the field in a red color). This will likely be changed at some point in
the future.
This commit adds parameter display functionality, via a wxPropertyGrid
widget, to the Sim Model Editor. To faciliate that, a SIM_VALUE class is
created to serialize, deserialize, and validate numeric values in the
new parameter grid.
SPICE_MODEL is renamed to SIM_MODEL and split into several subclasses
that correspond to different model kinds.