Use colors in HTML format, solving a warning about an unused function.

Use colors in HTML format, solving a warning about an unused function.

	* src/main/java/org/glom/web/shared/libglom/NumericFormat.java
	* src/main/java/org/glom/web/shared/libglom/layout/Formatting.java:
	Add *asHTMLColor() versions of methods.
	TODO: However, we should create and cache the results on the server.
	* src/main/java/org/glom/web/client/ui/details/DetailsCell.java
	* src/main/java/org/glom/web/client/ui/list/ListTable.java
	* src/main/java/org/glom/web/server/ConfiguredDocument.java
	* src/test/java/org/glom/web/server/libglom/DocumentTest.java:
	Use the asHTMLcolor() versions.