Fix latex high-level source editor in current version of cms / studio

Fix/cdodge/optimize metadata tree computation

Fix/will/capa response unit tests

Creating group for organization staff access DO NOT MERGE

were not being compiled before the LoncapaProblem initializer was
called.

remove unused import commands (which were used for temporary profiling). Also change get_lms_link_for_item() to preserve the previous argument ordering. Apparently all callers may not use argument name conventions for the 'preview' argument.

Bug/christina/misc

restore metadata inheritance. Fix lms jump computation on the Studio index page. This gets expensive.

use a different query to get all collections. Also don't apply inheritance to course modules, because that's ultimately a no-op

fix viewing of pdfbook on firefox

https://edx.lighthouseapp.com/projects/102637-studio/tickets/214-Via-Tender-Numerical-Input-answer-0-a-tolerance-is-not-accepted#ticket-214-4

https://edx.lighthouseapp.com/projects/102637-studio/tickets/214-Via-Tender-Numerical-Input-answer-0-a-tolerance-is-not-accepted#ticket-214-4

Added additional unit tests for symmath library that verify symmath_check for simple symbolic input strings.

studio - CodeMirror lines + cursor bug

Feature/cas/manual policy merged

Taking Ike's delete-student-state-for-problem code and putting it in a separate PR

Taking Ike's delete-student-state-for-problem code and putting it in a separate PR so it's not bundled with more debated features.

symmath_check for simple symbolic input strings.

Non-developer docs for course staff and researchers

Feature/brian/pdfchapter