Add block support to the tabular assertions

[Andrew Sullivan Cant]

This will be useful for checking the side effects of assertions.

inputs  :input1, :input2, :input3
it_with(:value1, :value2, :value3, :result) do
  # check side effects
end
side_effects_with(:value1, :value2, :value3) do
  # check side effects
end

[Andrew Sullivan Cant]

Never mind, this already works!