Since the webservices lessons are also created automatically by
Axis, which obviously does not have a reference to WebgoatContext,
and wouldn't call setWebgoatContext even if it did, we need to ensure
that each lesson created can still get to WebgoatContext.
Do this by maintaining a static reference to WebgoatContext that
all instances of the class can use.
git-svn-id: http://webgoat.googlecode.com/svn/trunk@165 4033779f-a91e-0410-96ef-6bf7bf53c507
7dee412ee1