remove haml requirement for running the base tests
this should remove the last 'hard' template test requirement that sinatra itself does not require.
I converted the encoding test to use erb. I figured since erb is in base ruby, and sinatra itself uses erb for the pretty showexceptions code -- this would be a win as it introduces no new base dependency.
this removes the last 'hard' template test requirement that sinatra itself does
closed by 8547387
Signed-off-by: Konstantin Haase <email@example.com>