Get rid of some 'the the' in comments and hints

Auditors: alex

Test Plan:
lint
Make line chart shorter so it fits better

Who needs 9 and 10, anyway?

Auditors: eater
Replace the protractor with a more better one

Test plan: "grep protractor exercises" to discover angle_types and measuring_angles are the only exercises to use the protractor. Open each of them in local mode, try each problem type, taking all hints.

Auditors: alex
Add Locale info to issue reports
Add lang var to issue sandcastle URLs
Merge pull request #82339 from theinternetftw/add-locale-to-issue-reports

Add Locale info to issue reports
Add a preview url function used by D4239.

Test Plan: see D4239

Reviewers: alpert

Reviewed By: alpert

CC: csilvers

Differential Revision: http://phabricator.khanacademy.org/D4241
Added movable angle construction to interactive.js

Summary:
Drag ray controls points to move rays, optionally snapping to
whole degree angles. Drag vertex to move entire angle.

Test Plan: Verified expected behavior in Perseus widget.

Reviewers: jack, eater

Reviewed By: jack

CC: alpert

Differential Revision: http://phabricator.khanacademy.org/D4392
Fix styles for MovableAngle.

math.js is currently loaded after interactive.js, so the standard colors
defined there aren't available when interactive.js is first parsed.

Test Plan:
Tested using the Angle subwidget in Perseus on local webapp and confirmed
that KhanUtil colors load correctly now.

Auditors: jack
Get rid of the check for _hashed-* files; those files are gone gone gone.

Summary:
I deleted the code that produces them 2 months ago.

I also added support for the new third_party directory I want to create.

Test Plan: Fingers crossed.

Reviewers: alpert, eater

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D4424
Move third party things to third-party; get rid of d3

Reworked 2 exercises that used d3 in a really pointless way

Test plan: Test exercises in local mode: reading_bar_charts_1, reading_line_charts_1, addition_1, graphing_linear_equations, matrix_addition_and_subtraction. For each, verify exercises render, no errors in console, hints work, and correct answer is accepted.

Auditors: csilvers, alpert
third_party, not third-party

Test plan: Open a few exercises that use third_party things in local mode and verify no console errors.

Auditors: csilvers
Fix up the lint blacklist now that third-party code is in third_party/.

I also fixed some lint errors in a file I thought was third-party
code, but it turns out is actually by us.

Auditors: eater

Test plan:
This passes without error:
   khan-exercises% ~/khan/devtools/khan-linter/runlint.py .
Minor changes to "Creating box and whisker plots"

Removed excess vertical and horizontal whitespace.
Added a bit more spacing between number line and number labels.

Test Plan:
Tested that exercise rendered correctly (no functionality changed).

Auditors: jack
Added a remove() method to the protractor.

Test Plan:
Verified no change in functionality on "Measuring angles" exercise.

Auditors: jack