Added ENABLE_MKTG_SITE to Features
Added myself to author file
Concept XBlock prototype
Switch from Rake to Paver
Change `if not args.skip_collect` to `if args.collect`

Simpler and clearer
from __future__ import print_function

and print errors and warnings to sys.stderr
write_stderr() function is unnecessary
Pull Paver requirements out into a separate file
Insert *right* at the front
Changed str->unicode in common/djangoapps/utils/.

LMS-2436
Merge
Merge pull request #3057 from edx/pmitros/concept-xblock-prototype

Concept XBlock prototype

Test environment taking a little longer than expect. Jarv said okay to merge, so merging,
Merge pull request #3032 from IONISx/feature-enable-mktg-site-is-missing

Added ENABLE_MKTG_SITE to Features
Display error page templates, for testing purposes

This commit allows us to test the server error template by visiting `/500`. This
way, we can catch errors in our error templates, instead of having infinitely
recursing errors.
Merge pull request #3060 from edx/db/display-error-pages

Display error page templates, for testing purposes
Fix Studio's XBlock dependency loading issues

STUD-1465

Changed the XBlock rendering logic to use promises to track asynchronous tasks.
Each dependency is then only loaded once the previous one has completed, and the
XBlock initialization only happens once all dependencies are loaded. This gives
XBlocks the same semantics in Studio as they get when shown directly on a page.
Merge pull request #3046 from edx/andya/fix-xblock-loading-in-studio

Fix Studio's XBlock dependency loading issues
Added template for iFrames. [BLD-611]
Merge pull request #3055 from edx/jmclaus/feature_iframe_template

Added template for iFrames. [BLD-611]
Submission history view not internationalized.
LMS-2167