1. Partial implementation of fo:region-xxx and background-color property

1.  Partial implementation of fo:region-xxx and background-color property
in AWTRenderer.

2.  ColorType has a new getAWTColor() method, also alpha() function renamed
to getAlpha(). Definition of Alpha values switched to make consistent with
java.awt.Color (i.e., 0 is transparent and 1 is opaque).

3.  AbstractRenderer's handleViewportTraits() renamed to handleRegionTraits()
to lesson confusion (FOP has three types of viewports--
Page, Region, and Block--handleViewportTraits() was only good for Region.)

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@196878 13f79535-47bb-0310-9956-ffa450edef68