[turbofan] Initial attempt to cleanup Node and related classes.

[turbofan] Initial attempt to cleanup Node and related classes.

- Make Node::Inputs and Node::Uses mostly STL compliant.
- Get rid of some pre-C++11 crappiness.
- Start moving unit tests from cctest to unittests.
- TrimInputCount() now tries to reserve inputs slots for
  later appending.
- Fix numerous style guide violations.

TEST=cctest,unittests
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/851263002

Cr-Commit-Position: refs/heads/master@{#26098}