#867 Waterheater default values are not valid,

The following command should not result in an error:
david:trunk david$ gridlabd --version --example residential:waterheater
GridLAB-D 3.0.0-4781 (Hatwai) 64-bit MACOSX RELEASE
WARNING  [INIT] : waterheater parent lacks 'air_temperature' property, using default
WARNING  [INIT] : waterheater parent lacks 'outside_temperature' property, using default
ERROR    [INIT] : watertank thermostat is set to 0.000000 and is outside the bounds of 90 to 160 degrees Fahrenheit (32.2 - 71.1 Celsius).
ERROR    [INIT] : init_waterheater(obj=0;unnamed): Tank UA value is negative.
WARNING  [INIT] : --example: unable to initialize example object from class waterheater
object waterheater:0 {

    // header properties
    rank 0;
    clock (invalid);
    flags (invalid);

    // waterheater properties
    tank_volume +20 gal;
    tank_UA +0 Btu/degF*h;
    tank_diameter +0 ft;
    water_demand +0 gpm;
    heating_element_capacity +0 kW;
    inlet_water_temperature +0 degF;
    heat_mode ELECTRIC;
    location INSIDE;
    tank_setpoint +0 degF;
    thermostat_deadband +0 degF;
    temperature +0 degF;
    height +0 ft;
    demand +0 gpm;
    actual_load +0 kW;
    previous_load +0 kW;
    actual_power +0+0i kVA;
    is_waterheater_on +0;
    gas_fan_power +0 kW;
    gas_standby_power +0 kW;
}

ERROR    [INIT] : watertank thermostat is set to 0.000000 and is outside the bounds of 90 to 160 degrees Fahrenheit (32.2 - 71.1 Celsius).
ERROR    [INIT] : init_waterheater(obj=0;unnamed): Tank UA value is negative.
ERROR    [INIT] : init_by_deferral(): object waterheater:0 initialization failed
ERROR    [INIT] : model initialization failed
FATAL    [INIT] : shutdown after simulation stopped prematurely
dump to 'gridlabd.xml' complete
FATAL    [INIT] : environment startup failed: Invalid argument
~~~~~,
nikhilgupta10 / GridLAB-D

#867 Waterheater default values are not valid, #2593
