Renamed functions

Hi Hugo,

first off I love your functions :) but.. I got conflicts with your function names. Especially function "debug" and "to-string" are no good names in my opinion. Also names of the other functions are really common and it is not clear that they are dealing with lists.

I tried to run your tests but I got this error message (even without any changes):
```
Syntax error: List index is 1 but list has no items for `nth'
        on line 11 of /Users/mm/Projekte/EigeneProjekte/SassyLists/node_modules/bootcamp/dist/utils/_stringify.scss, in `should'
        from line 8 of test/SassyLists/_chunk.scss, in `@content'
        from line 8 of /Users/mm/Projekte/EigeneProjekte/SassyLists/node_modules/bootcamp/dist/core/mixins/_it.scss, in `it'
        from line 7 of test/SassyLists/_chunk.scss, in `@content'
        from line 14 of /Users/mm/Projekte/EigeneProjekte/SassyLists/node_modules/bootcamp/dist/core/mixins/_describe.scss, in `describe'
        from line 1 of test/SassyLists/_chunk.scss
        from line 8 of ./test/test.scss
  Use --trace for backtrace.
```

There also was a syntax error in your gruntfile (missing comma).

Greetings