Add Spek audio spectrum analyzer
user
```ruby
class Spek < Cask
  url 'https://spek.googlecode.com/files/spek-0.8.3.dmg'
  homepage 'http://spek.cc'
  version '0.8.3'
  sha1 'b66d940180991788346fd6abacb2f6c2f01c4351'
  link 'Spek.app'
end
```
assistant