CLC-1464 Use Rails_Admin to manage My Campus Links

Squashed commit of the following:

commit 72ae22ea9140770acbd28cff3a349848204b4c52
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jun 11 13:16:53 2013 -0700

    CLC-1464 Fix labels, only allow root cats as root cat of sections

commit aa81fd1bce3cd1284f9e625f49c61136c3503e06
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jun 11 12:41:31 2013 -0700

    CLC-1464 Provide way for admin to expire the link cache

commit 310148005b7610c2b740665bfc960a7fe8cfa790
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jun 11 12:32:16 2013 -0700

    CLC-1464 Import campuslinks.json as a migration

commit b1488755838d16dba2bd63ccfe07f54986eda842
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jun 11 08:29:19 2013 -0700

    CLC-1464 Renaming main_cat to root_cat

commit d4c80f99c8e789fd407b2612c2d19edbee10a821
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Mon Jun 10 16:05:59 2013 -0700

    CLC-1464 First start at data loading for campus links

commit 2e690a6968a7a342beef00e15da19210e763b12e
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Mon Jun 10 15:04:49 2013 -0700

    CLC-1464 Rename migration file

commit 30b2f5d4a612c8b38696f472d864fd9bff028098
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Mon Jun 10 14:43:03 2013 -0700

    CLC-1464 Consolidate migrations into one file

commit e49c5f51f53ef5e41e24d7fe37bb1c04289659e4
Author: Scot Hacker <shacker@birdhouse.org>
Date:   Fri May 31 17:59:02 2013 -0700

    CLC-1464 RailsAdmin for data management; CampusLinks generation
    https://jira.media.berkeley.edu/jira/browse/CLC-1464

    - This commit should satisfy all notes from Chris' code review.

    - Reference to the new JSON feed is commented out in campusController.js so this can go live any time without affecting anything else. Just toggle that when ready.

    - Sorry I didn't have time to work on data import/export, but we felt it was more important to get the data structure right.
[NOJIRA] Explicit requires needed for ProcessControl
[CLC-2022] Suppress exam schedules that do not match current_term and current_year
CLC-2020 - In My Academics > Summary, change "Status and Blocks" to "Blocks" and remove Status Type.
https://jira.media.berkeley.edu/jira/browse/CLC-2020
Merge pull request #1175 from yuhunglin/CLC-2022

[CLC-2022] Suppress exam schedules that do not match current_term and current_year
Merge pull request #1173 from yuhunglin/NOJIRA

[NOJIRA] Explicit requires needed for ProcessControl
Merge pull request #1176 from christianv/CLC-2020

CLC-2020 - In My Academics > Summary, change "Status and Blocks" to "Blo...
Merge pull request #1172 from ctweney/clc-1464-squash

CLC-1464 Use Rails_Admin to manage My Campus Links
NOJIRA Darlene's tweaks to act-as script so it runs on Linux
Merge pull request #1178 from ctweney/act-as-audit-tweak

NOJIRA Darlene's tweaks to act-as script so it runs on Linux
CANVAS-114 Refresh Canvas section memberships from campus data
CANVAS-114 Loop while checking Canvas report generation; added test & shell script