This commit adds validation for course advanced settings. Currently when course
administrators make invalid changes in the Settings/Advanced Settings tab,
they're not notified through a new modal window of the list of invalid settings
changes.

* Extending CourseMetadata
    - Previously, we only had update_from_json method in CourseMetadata.py,
      and it was only validating one field every POST request.
    - Now we have validate_and_update_from_json method that encapsulates the
      functionality of update_from_json into a validation call
    - To avoid discrepancy of validation standards between modules, validation
      uses the from_json method implemented to each field in xblock.

* Different Response in advanced settings ajax requests
    - After receiving a POST ajax request, course.py calls
      validate_and_update_from_json, and sends a json object of either:
        1) valid course metadata model
        2) error objects

* Error Messages shown in validation-error-modal
    - error objects passed through ajax are shown in a separate modal.

Studio: adding course re-run-centric static template rendering

* initial HTML for dashboard states
* initial HTML for new course re-run view/form
* initial HTML placeholder for outline alert UI

Conflicts:
	cms/templates/index.html

Studio: adding styling for course re-run-centric views

* adding new view/page mast-wizard type
* refactoring create course/element form styling
* adding course re-run view specific styling
* adding courses processing styling (w/ alerts and status)

Course rerun server-side updates: support display_name and DuplicateCourseError.

Studio: further design revisions and tweaks from feedback

* removing new window attribute from re-run control
* removing links from processing courses
* revising look/feel of dismiss action on dashboard + alert
* correcting font-weight of dashboard processing title
* adding extra space to course rerun action on dashboard
* re-wording secondary cancel action on rerun view

Conflicts:
	cms/templates/index.html

Added interation on unsucceeded courses in dashboard

Studio: removing 'rel=external' property from course re-run actions

Studio: removing hover styles for processing courses

Fixed value bug in split and set course listing to display run

moved task.py for rerun

STUD-2113

* moving font-size to use @include font-size() mixin
* re-organizing vendor reset styling into _vendor.scss override rather than _reset.scss
* initial rule re-organization and minor line-height tweaks

* adding back in drag and drop indicators to outline DOM
* correcting visual display of drag action in outline UI
* adjusting styling of outline drag and drop indicators
* adjusting styling of drag and drop was-dropped state

* syncing up status-release hover states for outline units
* adjusting in-context editor UI for longer outline titles
* corrects outline incontext editor display regression
* cleaning up unit/container sidebar styling
* removing redundant margin on Outline UI subsections
* selecting text when a user focuses into an incontext-editor input - STUD-2032

* correcting visual display of outline UI without content
* temporarily resolving page actions that should be hidden by default

* syncing up unit publishing state UI with stateful names/styles
* revising outline item status message display logic to show release status
* fixing publishState value typo in outline UI template
* refining and syncing incontext editor styling
* maintaining visual alignment of collapsed/expanded sections in outline UI
* simplifying page-level action styles on outline UI

STUD-1873

STUD-1726

Conflicts:
	cms/djangoapps/contentstore/views/item.py

styling for editing a live unit

cleanup of unit, container, and xblock sass; added modules and layout sass; publishing states and actions on new unit

STUD-1754

STUD-302, STUD-303