Triangle facts 20140929 rc

Updates:
-`sides` method created and used where applicable
-variable renaming in `calculate_angles` method

Side note: this led to the lines being longer than 80 chars, so i broke the lines out based on this style guide: https://github.com/thoughtbot/guides/blob/master/style/samples/ruby.rb#L62-L66

@bwthomas Is this type of formatting acceptable/practiced in the Enova coding environment?
Yeah, I was set to close it until I read this.

So, some people hate case statements. I don't, but I'm suspicious of them. The other thing that bugs me about this is that it's a method name with the suffix _type, but then it's returning what is essentially a string description so it looks more like a presenter.

personally, in this case I'd write something like this:

```
def triangle_type
  unique_sides = sides.uniq.count
  return :equilateral if unique_sides == 1
  return :isosceles   if unique_sides == 2
  return :scalene     if unique_sides == 3
end
```

Then I'd have a presenter that basically does a lookup in a hash for the specific verbiage.