Implement new styles for line charts
Implement new styles for line charts

Summary: Implements new colors, point styles, and adds dragging prompt to line charts so that they match up with the mockups.

Test Plan:
- Verified in Perseus demo that line charts have all new styles defined in the mockups
- Verified that without the xomManatee flag line charts look the same

Reviewers: kevinb

Reviewed By: kevinb

Subscribers: jared

Differential Revision: https://phabricator.khanacademy.org/D29665

ariabuckles/perseus,ariabuckles/perseus,ariabuckles/perseus,learningequality/perseus,ariabuckles/perseus,learningequality/perseus