Feature flagged enrollment counts on instructor dashboard.

* enrollments counts removed from legacy dashboard
Fix spelling of complementary role
added tests for instructor_dashboard.py, added docstring for _is_small_course, removed check for settings.ANALYTICS_DASHBOARD_URL when creating dashboard link
Pylint: ignore TODO comments
Disable TODO comments in `paver quality` only
Disable FIXME errors on `paver run_quality`

Not on `paver run_pylint`
Wrap pymongo connections in MongoProxy.

PLAT-71
Added autoretry_read decorator to methods which use mongo cursor.

PLAT-71
Wrapped Split MongoConnection in MongoProxy.

PLAT-71
fixed quaility errors in instructor_dashboard.py, moved test_instructor_dashboard under tests/views directory
Remove unused images
Moved images in folders to top level where appropriate, and change references.

OPEN-297
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