Fix all-your-base test. For great justice!

[rmunn]

Fixes #206 by allowing any number of sequential zeroes to represent 0, but considering an empty list of digits to still be an error. (We can fix that one later if necessary).

[rmunn]

The AppVeyor build runs the tests, but the Travis build doesn't? Weird.

... Oh, I see. The Travis build is honoring the Ignore attribute, but for some reason the AppVeyor build is actually ignoring the Ignore attribute and running the marked-as-ignored tests anyway. And the tests are failing because I updated the tests, but I didn't update the example code.

I'd rather not update the example code until after I do the exercise myself, so that I come at it fresh. If someone else wants to update the example, that would be great. Otherwise, I'll get to it, but it might be a couple of days.

[ErikSchierboom]

Odd that the Travis build succeeds, it should have the same behavior. Both build servers should indeed run all tests, including those marked as ignored. The rationale behind that is that we want to be sure that our example code passes all tests.

I can look into fixing the example code monday probably.

[ErikSchierboom]

@rmunn I saw that you posted a correct implementation that works with the modified tests on exercism. Would you mind adding your correct implementation to this PR as the example implementation for this exercise?

[rmunn]

@ErikSchierboom New example implementation added, all tests passing. PR should be ready to merge now.

[ErikSchierboom]

Merged. Thanks! 🎉