[T5] Improving exception message when using @Environmental

[Kristian Marinkovic <kr...@porsche.co.at>]

hi,

i pushed an own helper class (ParentHelper) into the Environment instance 
to make it usable in one of my nested components using @Environmental. 

But instead i got the following exception although i used the correct 
class: 
No object of type com.poi.tapestry5.experiment.components.ParentHelper is 
available from the Environment. 
Available types are com.poi.tapestry5.experiment.components.ParentHelper, 
org.apache.tapestry.MarkupWriter, ... 
org.apache.tapestry.services.Heartbeat. 

After thinking twice (and after 2h of testing) i realized that the 
location of 
my helper class was within the component package and everything in there 
would get enhanced. Moving it to another package solved the problem. 

I was wondering whether it were possible to mark enhanced classes in a
way they could be easily distinguisehd from non-enhanced classes so the
above exception would be easier to understand. At least from the 
exceptions
messages....

g,
kris