add trouble-shooting tips

[plastikfan]

• command not found: make sure the command builder is invoked from the bootstrapper
• panic: runtime error: invalid memory address: make sure you don't invoke Text, before Use has been invoked
• make sure that for all enum members of a command's parameter set, that NewValue() is invoked to create the enum value (actually this should be set into the bound field, when its has been defined, see issue add an enum bound field #147) inside the command builder function.