Tk#411 - 3.3: Use of explicit uom within SE Styles

http://tracker.deegree.org/deegree-services/ticket/411

With this enhancement it's possible to overwrite the unit of measure (attribute "uom") for symbolizers setting the value for "stroke-width" or other options using "px" after the number. Ex.:

<se:PolygonSymbolizer uom="mm">
    <se:Stroke>
        <se:SvgParameter name="stroke-width">3px</se:SvgParameter>
    </se:Stroke>
</se:PolygonSymbolizer>


I implemented this feature for the next symbolizers and options:

PolygonSymbolizer: Stroke-width - PerpendicularOffset - Gap;

LineSymbolizer: Stroke-width - PerpendicularOffset - Gap;

TextSymbolizer: LinePlacement?: PerpendicularOffset - PointPlacement: Displacement