Fix issue w/ windspeedmph in Weather Shield w/ GPS

I fixed the issue with the _windspeedmph_ in the _Weather_Shield_Weather_Station.ino_ example code [ [https://github.com/sparkfun/Weather_Shield/pull/25](https://github.com/sparkfun/Weather_Shield/pull/25) ]. However, this was also an issue with the _Weather_Shield_with_GPS.ino_ .

Fixed output for windspeedmph and gps longitude 

formatting code on line 179

Adding line of code at 178:

    windspeedmph = currentSpeed;//update global variable for windspeed when using the printWeather() function

and added comment to line 227 to explain why the calculation was commented out:

    //windspeedmph = get_wind_speed(); //This is calculated in the main loop on line 179

to fix this issue => https://github.com/sparkfun/Weather_Shield/issues/24

changed line 445 to   Serial.print(",lng="); to fix this issue:

https://github.com/sparkfun/Weather_Shield/issues/23

Fritzing file now located in Fritzng_Parts

Bug call getWindSpeed twice get Nan result

Adding explicit note for additional libraries location to run demo code.

Added slots to allow better airflow around sensors.

Many schematic and routing changes. See issues.