nucleotides test and example in coffeescript

I squashed the commits together into one and renamed the main file. I think I have done everything correctly, but if there is something else let me know :)
You can also say:

```
if nucleotide is 'U' then 0 else strand.split(nucleotide).length - 1
```

or

```
if nucleotide is 'U'
	0
else
	strand.split(nucleotide).length - 1
```