Errors should be more user-friendly

[novatia]

Running on default ANSI 104 layout gives cryptic error:

ERROR: Key placement produced too many columns. klepcbgen currently cannot generate a valid KiCad project for this keybo
ard layout.

Need to check code to understand what is wrong with the layout and correct the JSON layout.

A hint on how to change the configuration file could be more usefull instead of logic error description.

I can't give you a precise example but something like "on row XX, this parameter can't be managed"
Or in this case "keyboard can't have more than XX columns sry."