Merge pull request #602 from acornacorn/groovy-devel

preserve alpha when using setColor()
GoalTool: changed '/move_base_simple/goal'->'goal'

for backwards compatibility (see http://answers.ros.org/question/56773/rviz-goal-topic-fuerte-vs-groovy/)
Fixed bug in ColorEditor which showed up on TWM.  Thanks Acorn!
position link axis on creation.