ion_envcan. Make fully unit friendly. Converts metric and imperial based on KDE system settings. Fix prevPecip value, may also return Trace instead of 0 for totals. Fix up comfort temperature to also handle imperial values.

Fix some cases if fields are blank return N/A for stationID. Ditto for temperature, dewpoint, humidity. Add new conversion functions centimetersToMI, inchesToCM, millimetersToIN, inchesToMM, change function some function names.