Got rid of another magic number.
Implemented sequencer in Arduino C.

It doesn't have an interfcae yet, but it does have a preset pattern.

Squashed commit of the following:

commit bfcd89251a866da548aec006e72a1cfc7acce833
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:35:13 2012 +0100

    Commented out DAC writing line.

    I don't yet know if this works.

commit 94e7310bc73c3009c955833ff288dead197add3a
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:32:53 2012 +0100

    Added DAC function.

    Theoretically, it should now be able to write to a DAC, were one
    installed.

    Let's find out later on...

    So far, it just stops the LED flashing, although the code does compile
    without errors.  But then again, we haven't installed a DAC yet.

commit abe6b42f80296d9060489b1ff7e798afe0c83217
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:22:32 2012 +0100

    No it doesn't.

    Looping a pattern should *not* cause it to reload, that would be too
    much overhead.  I put in a condition for that a few commits ago.

    Revert "See comment."

    This reverts commit 0a82db1a3c84da5fb1805784d6b3c66941d2ad6e.

commit 0a82db1a3c84da5fb1805784d6b3c66941d2ad6e
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:22:27 2012 +0100

    See comment.

commit 4a883bdf576ff014e6c0149b511105991f43a2a9
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:17:37 2012 +0100

    Renaming variables.

    Again, this is to bring them in line with other varible names.

commit 354561f86740af7a13cbd3ab6c9b4070fc73cdc0
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:15:08 2012 +0100

    Commenting, refactoring.

commit d10dd3ba059fcafa7c4346c655cd5221625dcf35
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:12:01 2012 +0100

    Bugfixes.

    Bearing in mind my only means of testing this is by changing what
    gets echoed out to the built-in LED.  :)

commit bc422f4321ce9122fd11cc9e6d6f06ef297a6c10
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 14:06:52 2012 +0100

    (Hopefully) programmed in a preset pattern.

    The final version probably shouldn't do this, but it's necessary
    before we've added an interface to let people program in their own
    patterns.

commit 232d3ba90ea710bde5af75af15e2d67b0d51c36c
Merge: b671b71 30bc8fe
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 12:33:12 2012 +0100

    Merge branch 'master' into c-seq

commit b671b71908bb17ac076a1435040525807b093b15
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 12:32:06 2012 +0100

    Implemented the run/stop button.

commit 8a19e68bc68bd53b94b42864da2900da9605045f
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 12:25:59 2012 +0100

    (Theoretically) implemented the clipboard etc.

commit 1f779b696e1ab55a1ee049ad3b2fb9934da00039
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 12:06:40 2012 +0100

    Minor renaming and refactoring.

commit beaf51414ba1c7454874b4022f3ab762e2b91cd2
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 11:57:17 2012 +0100

    (Theoretically) added digital output of gate and accent.

commit d08cfa1114e9185576d2de526474845249d66acf
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 11:46:51 2012 +0100

    Accent is now read from the pattern buffer.

commit 03bdcf043ddf3984b34379fe9151b01f204d7b93
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 11:45:11 2012 +0100

    Translated more of sequencer.

commit 4778a629187ccfae2a21d8c6eb8b9652d1845ac2
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 11:24:29 2012 +0100

    Refactored.

    Less variable copying.  Less simple, but faster.

commit e95d67e0c261abb18d5f4143b9e158929395db67
Author: Zoë Blade <zoe@bytenoise.co.uk>
Date:   Sun May 27 11:22:28 2012 +0100

    More translating, about to refactor.