change internal structure of ActionT. add response function.
remove unneed data type. add MonadCatch, MonadMask instance ActionT, add INLINE pragma runActionT, actionT
version bunp up. default wai3. fixed #8.
fix ifdef case.
export response function, fix build failure on StreamingBody export, fix dependencies.
remove tagged dependency when ghc >= 7.8.
Merge branch 'develop'

wai-3.0.
add respose function.
add MonadCatch, MonadMask instances.