GitLab

Restructure contents of blimp/client folder. See crbug.com/581506
for more information on the eventual directory structure.
Modify paths and ifdef guards as needed.
Resolve various linter errors encountered along the way.
Add TODOs for missing documentation.

R=dtrainor@chromium.org,haibinlu@chromium.org
BUG=581506

Review URL: https://codereview.chromium.org/1636163002

Cr-Commit-Position: refs/heads/master@{#371684}