support servant-0.16

[imalsogreg]

Thanks @snoyberg for reporting this.

servant-0.16 is out and there are several breaking changes for us to work around.

[imalsogreg]

From the original ticket:

[3 of 6] Compiling Servant.Checked.Exceptions.Internal.Servant.Server ( src/Servant/Checked/Exceptions/Interna
l/Servant/Server.hs, dist/build/Servant/Checked/Exceptions/Internal/Servant/Server.o )

src/Servant/Checked/Exceptions/Internal/Servant/Server.hs:49:5: error:
    Module
    ‘Servant.Server.Internal.RoutingApplication’
    does not export
    ‘Delayed’
   |
49 |   ( Delayed
   |     ^^^^^^^

src/Servant/Checked/Exceptions/Internal/Servant/Server.hs:50:5: error:
    Module
    ‘Servant.Server.Internal.RoutingApplication’
    does not export
    ‘DelayedIO’
   |
50 |   , DelayedIO
   |     ^^^^^^^^^

src/Servant/Checked/Exceptions/Internal/Servant/Server.hs:51:5: error:
    Module
    ‘Servant.Server.Internal.RoutingApplication’
    does not export
    ‘RouteResult(FailFatal, Route)’
   |
51 |   , RouteResult(FailFatal, Route)
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/Servant/Checked/Exceptions/Internal/Servant/Server.hs:52:5: error:
    Module
    ‘Servant.Server.Internal.RoutingApplication’
    does not export
    ‘addAcceptCheck’
   |
52 |   , addAcceptCheck
   |     ^^^^^^^^^^^^^^

[cdepillabout]

I'm not sure when I'll get a chance to fix this, but if someone wants to send a PR getting in support for Servant-0.16, I'll make it a priority to merge in.

Also, if you want to drop support for versions of Servant less than 0.16, I'd be fine with that as well.