Construct the Grothendieck construction a pfunctor

We finally have the categorical analogue of the sigma types.  Following
the advice of Paolo Capriotti, I've split it up into the following
parts:

- Every pseudofunctor to Cat can but sigma'ed to a category of elements
- Every functor is a pseudofunctor

It's really, really slow, though. :-(  I think it's because the terms
are so big.

After    | File Name                             | Before
-----------------------------------------------------------
4m49.42s | Grothendieck/PseudofunctorToCat       |   N/A
1m02.49s | Pseudofunctor/FromFunctor             | 1m02.53s
0m24.84s | Pseudofunctor/Core                    | 0m25.85s
0m23.37s | Category/Equality                     | 0m24.02s
0m22.20s | Comma/Duals                           | 0m22.64s
0m21.86s | Adjoint/Hom                           | 0m22.45s
0m12.56s | Adjoint/Composition                   | 0m12.22s
0m12.36s | Adjoint/Duals                         | 0m11.79s
0m12.23s | Adjoint/UniversalMorphisms            | 0m13.08s
0m10.68s | Adjoint/UnitCounitCoercions           | 0m10.58s
0m08.27s | Comma/InducedFunctors                 | 0m08.12s
0m07.26s | Groupoid                              | 0m07.47s
0m06.41s | Adjoint/Equality                      | 0m06.38s
0m06.20s | Category/Morphisms                    | 0m06.51s
0m05.88s | Adjoint/UnitCounit                    | 0m05.76s
0m04.62s | Groupoid/Duals                        | 0m04.50s
0m04.57s | SumPreCategory                        | 0m04.86s
0m04.22s | Functor/Equality                      | 0m04.18s
0m03.95s | Groupoid/Functors                     | 0m03.60s
0m03.60s | UniversalProperties                   | 0m03.25s
0m02.83s | Grothendieck/ToSet                    | 0m02.75s
0m02.79s | Comma/CommaCategory                   | 0m02.64s
0m02.36s | BoolCategory                          | 0m02.49s
0m02.32s | NaturalTransformation/Pointwise       | 0m02.42s
0m01.89s | Hom                                   | 0m01.75s
0m01.88s | NaturalTransformation/Duals           | 0m01.79s
0m01.85s | Category/Product                      | 0m01.96s
0m01.84s | FunctorCategory/Morphisms             | 0m01.82s
0m01.82s | NaturalTransformation/Isomorphisms    | 0m01.90s
0m01.78s | NaturalTransformation/Equality        | 0m01.73s
0m01.48s | NaturalTransformation/Product         | 0m01.45s
0m01.29s | NaturalTransformation/CompositionLaws | 0m01.28s
0m01.29s | NaturalTransformation/Composition     | 0m01.38s
0m01.28s | Functor/Product                       | 0m01.27s
0m00.58s | InitialTerminalCategory               | 0m00.62s
0m00.50s | Functor/Pointwise                     | 0m00.46s
0m00.46s | Functor/CompositionLaws               | 0m00.44s
0m00.42s | Comma/Projection                      | 0m00.42s
0m00.36s | Discrete/Duals                        | 0m00.36s
0m00.35s | IndiscreteCategory                    | 0m00.42s
0m00.35s | Common                                | 0m00.31s
0m00.34s | SetCategory                           | 0m00.32s
0m00.30s | Cat                                   | 0m00.27s
0m00.28s | Cat/Morphisms                         | 0m00.31s
0m00.28s | Functor/Duals                         | 0m00.25s
0m00.28s | FunctorCategory                       | 0m00.30s
0m00.27s | NaturalTransformation/Identity        | 0m00.29s
0m00.27s | Grothendieck/ToCat                    |   N/A
0m00.24s | Category/Objects                      | 0m00.24s
0m00.23s | IsGroupoid                            | 0m00.21s
0m00.23s | NatCategory                           | 0m00.20s
0m00.23s | Functor/Composition                   | 0m00.23s
0m00.19s | Category/Core                         | 0m00.20s
0m00.19s | NaturalTransformation/Core            | 0m00.12s
0m00.17s | Adjoint                               | 0m00.14s
0m00.17s | NatCategory/Duals                     | 0m00.16s
0m00.17s | ComputableCat                         | 0m00.18s
0m00.15s | Adjoint/Identity                      | 0m00.16s
0m00.14s | Category/Duals                        | 0m00.15s
0m00.13s | DiscreteCategory                      | 0m00.10s
0m00.13s | NaturalNumbersObject                  | 0m00.15s
0m00.13s | Pseudofunctor                         | 0m00.16s
0m00.12s | NaturalTransformation                 | 0m00.09s
0m00.12s | Functor/Core                          | 0m00.11s
0m00.12s | Peano                                 | 0m00.13s
0m00.11s | Grothendieck                          | 0m00.14s
0m00.09s | Functor/Identity                      | 0m00.10s
0m00.09s | Functor                               | 0m00.06s
0m00.09s | Utf8                                  | 0m00.10s
0m00.09s | Category/UnivalentCategory            | 0m00.10s
0m00.08s | Category                              | 0m00.06s
0m00.07s | Category/StrictCategory               | 0m00.08s
0m00.05s | Notations                             | 0m00.05s
0m00.04s | NotationsUtf8                         | 0m00.04s
-----------------------------------------------------------
9m42.30s | Total                                 | 4m54.64s