Replaced //site/weather with a new //project/designParameters element

[grimsa]

Removed //site/weatherData in favor of a new //project/designParameters element.

The new element holds info about codes that apply, temperature datasets and structural design parameters. Example:

<iep:designParameters>
  <iep:codes>
    <iep:code type="FIRE" codeBody="CALIFORNIA" edition="2016"/>
    <iep:code type="ELECTRIC" codeBody="NATIONAL_FIRE_PROTECTION_ASSOCIATION" edition="2016"/>
  </iep:codes>
  <iep:temperature>
    <iep:temperatureDataset type="HIGH" source="ASHRAE" dateRecorded="2017-07-30" description="Optional comment or description of the dataset">
      <iep:temperatureDataPoint type="HIGHEST_MONTH_TWO_PERCENT_DRY_BULB">32</iep:temperatureDataPoint>
      <iep:temperatureDataPoint type="MAXIMUM_MEAN_EXTREME_DRY_BULB">38</iep:temperatureDataPoint>
    </iep:temperatureDataset>
    <iep:temperatureDataset type="HIGH" source="HISTORIC" dateRecorded="2015-01-22">
      <iep:temperatureDataPoint type="HIGHEST_MONTHLY_AVERAGE">29</iep:temperatureDataPoint>
    </iep:temperatureDataset>
    <iep:temperatureDataset type="LOW" source="HISTORIC" dateRecorded="2015-01-22">
      <iep:temperatureDataPoint type="RECORD_LOW">-8</iep:temperatureDataPoint>
    </iep:temperatureDataset>
  </iep:temperature>
  <iep:structuralDesign>
    <iep:asceEdition>ASCE_7_10</iep:asceEdition>
    <iep:windExposureCategory>B</iep:windExposureCategory>
    <iep:topographicalCondition>STANDARD</iep:topographicalCondition>
    <iep:designWindSpeed unit="MILES_PER_HOUR">110</iep:designWindSpeed>
    <iep:specialWindRegion>false</iep:specialWindRegion>
    <iep:groundSnowLoad>0</iep:groundSnowLoad>
  </iep:structuralDesign>
</iep:designParameters>

Note:

1. Enumerations are used extensively, but I'm not sure if I have specified all the required values.
2. weatherData type was removed from CommonSolar.xsd, because it was not used anywhere.