Revert "Rewrites RootContext#initialize as per @sferik's suggestion"

This reverts commit 8abc3fd0fc972755af064d124100048c924b2e12.
Revert "Calls block directly instead of instance_eval'ing it"

This reverts commit 92936b36cee945f56aace7b1db3df7810abcf380.
renames blocks to something more explicit