pylint cleanup.
Merge pull request #5560 from edx/benp/improve-pylint-violations

pylint cleanup.
add Solano CI.
Merge PR#3. Solano: Add post worker hook for copying artifacts.
fixed capturing screenshots
adding post worker script
fixing file log error
introduce bok-choy shards, new firefox version
re-shard lms to fix a failing test.
Add quality report capability.
Merge Coverage Reports
TE-465
Upgrade to mongo 2.6.4
Publish datadog stats for build
TE-453