First cut at ResultsRaster WPS process for rasterization of transects based on calculated results using SLD Rendering Transform

Needs work, but gives us an service interface to play with and determine if this is a desirable rendering methodology (ie. should we use WFS, WMS or WMS-in-browser-colormap).  Just colors transects in greyscale based on auto-range of selected results variable. Will generate and fill polygons, and look at other color maps soon.

Sample SLD to enable:

```xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0.0" xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd">
  <NamedLayer>
    <Name>ResultsRaster</Name>
    <UserStyle>
      <Title>ResultsRaster</Title>
      <Abstract>ResultsRaster</Abstract>
      <FeatureTypeStyle>
        <Transformation>
          <ogc:Function name="gs:ResultsRaster">
            <ogc:Function name="parameter">
              <ogc:Literal>features</ogc:Literal>
            </ogc:Function>
            <ogc:Function name="parameter">
              <ogc:Literal>attribute</ogc:Literal>
              <ogc:Literal>LRR</ogc:Literal>
            </ogc:Function>
            <ogc:Function name="parameter">
              <ogc:Literal>bbox</ogc:Literal>
              <ogc:Function name="env">
                <ogc:Literal>wms_bbox</ogc:Literal>
              </ogc:Function>
            </ogc:Function>
            <ogc:Function name="parameter">
              <ogc:Literal>width</ogc:Literal>
              <ogc:Function name="env">
                <ogc:Literal>wms_width</ogc:Literal>
              </ogc:Function>
            </ogc:Function>
            <ogc:Function name="parameter">
              <ogc:Literal>height</ogc:Literal>
              <ogc:Function name="env">
                <ogc:Literal>wms_height</ogc:Literal>
              </ogc:Function>
            </ogc:Function>
          </ogc:Function>
        </Transformation>
        <Rule>
          <RasterSymbolizer>
            <!-- specify geometry attribute to pass validation -->
            <Geometry>
              <ogc:PropertyName>the_geom</ogc:PropertyName>
            </Geometry>
          </RasterSymbolizer>
        </Rule>
      </FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>
```