Parital implementation of finalizers.

See #111.

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index.js                 13370/13.06  4356/04.25  3738/03.65  1619/01.58
Test that fixup not callled on error.

Testing that fixups are not called on error. Need to assert this in
order to make modifications to the implementation of fixups to support
finalizers.

See #111.

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index.js                 13370/13.06  4356/04.25  3738/03.65  1619/01.58
Move argument extraction to separate function.

Move argument extraction to a separate function so that we can call
`invoke` directly with arguments, without having to create bogus
`callback` arrays. Necessary to create a more robust implementation of
exceptions and finalizers.

See #111.
See #110.
See #105.

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index.js                 13417/13.10  4364/04.26  3715/03.63  1612/01.57
Notes on object properties.
Remove unused variables.
All callbacks return errors array.

Within the Cadence implementation, callbacks given to `begin` will
accept an array of errors as their first argument. An empty array
indicates no errors.

See #111.
See #110.
See #105.

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index.js                 13300/12.99  4369/04.27  3681/03.59  1608/01.57
Unfold a new cadence just prior to a run

See #111.
See #110.
See #105.

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index.js                 13407/13.09  4405/04.30  3707/03.62  1614/01.58
Propagate finalizers from a cadence.

Propagate finalizers from a completed cadence to the callback given to
the `begin` function. This allows fixup finalizers the option of merging
the finalizers into the list of finalizers of the calling cadence.

See #111.
See #110.
See #105.

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index.js                 13931/13.60  4632/04.52  3788/03.70  1689/01.65
Implemented finalizers.

More tests would be nice, but I'll create separate issues for each
aspect of finalizers I want to test.

Closes #111.
See #110.
See #105.

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index.js                 14014/13.69  4636/04.53  3816/03.73  1688/01.65
Merge branch `finalizers` into `master`.