copied .gitignore from spire
General clean up.

Mostly, this was a cosmetic clean up. I removed the target/ files from
Git, since those will change every compile. I cleaned up the whitespace
and formatting of the 3 scala files.

I also did a bit more substantial work, included:

1. Replacing ring.plus(x, y) with x + y
2. Using more of Spire's array methods, qmin, qsum, etc
3. Trying to minimize sorting, and reduce code size a bit
remove E as generic type
refactored underlying poly data
Refactor many uses of Polynomial#terms to use underlying map.
Merge pull request #1 from non/topic/array-to-map-refactor

Topic/array to map refactor