Add jQuery migrate for more awesome compatibility
Upgrade jQuery UI and fix the shake

Auditors: eater, cbhl
Add new problem type to solving_for_the_y-intercept

Test Plan: local mode in chrome

Reviewers: cbhl

Reviewed By: cbhl

CC: alpert

Differential Revision: http://phabricator.khanacademy.org/D2079
Don't change the width of All The Answers

Test plan: looked at the answer area

Auditors: cbhl
Fix timeline for radio/custom when correct answer isn't given

Fix #41306

Test plan: Check that each of the following now do the right thing:
http://localhost:8000/exercises/recognizing_rays_lines_and_line_segments.html?debug&problem=line-segment&seed=193&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%22Ray%5C%22%22%2C5%5D%2C%5B%22incorrect-activity%22%2C%22%5C%22Line%5C%22%22%2C1%5D%2C%5B%22correct-activity%22%2C%22%5C%22Line%20segment%5C%22%22%2C2%5D%5D

http://localhost:8000/exercises/recognizing_rays_lines_and_line_segments.html?debug&problem=line-segment&seed=193&activity=%5B%5B%22incorrect-activity%22%2C%22%5C%22Ray%5C%22%22%2C8%5D%2C%5B%22incorrect-activity%22%2C%22%5C%22Line%5C%22%22%2C1%5D%5D

http://localhost:8000/exercises/balancing_chemical_equations.html?debug&problem=mgoh2-hcl---mgcl2-h2o&seed=32&activity=%5B%5B%22incorrect-activity%22%2C%22%5B%5C%222%5C%22%2C%5C%22%5C%22%2C%5C%222%5C%22%2C%5C%22%5C%22%5D%22%2C6%5D%2C%5B%22incorrect-activity%22%2C%22%5B%5C%222%5C%22%2C%5C%222%5C%22%2C%5C%222%5C%22%2C%5C%22%5C%22%5D%22%2C3%5D%2C%5B%22incorrect-activity%22%2C%22%5B%5C%222%5C%22%2C%5C%22%5C%22%2C%5C%222%5C%22%2C%5C%22%5C%22%5D%22%2C10%5D%2C%5B%22correct-activity%22%2C%22%5B%5C%22%5C%22%2C%5C%222%5C%22%2C%5C%22%5C%22%2C%5C%222%5C%22%5D%22%2C6%5D%5D

http://localhost:8000/exercises/balancing_chemical_equations.html?debug&problem=mgoh2-hcl---mgcl2-h2o&seed=32&activity=%5B%5B%22incorrect-activity%22%2C%22%5B%5C%222%5C%22%2C%5C%22%5C%22%2C%5C%222%5C%22%2C%5C%22%5C%22%5D%22%2C3%5D%2C%5B%22incorrect-activity%22%2C%22%5B%5C%224%5C%22%2C%5C%222%5C%22%2C%5C%224%5C%22%2C%5C%22%5C%22%5D%22%2C8%5D%5D

Auditors: cbhl, alpert
Start arithmetic series word problems
Add description of shapes
Remove unrelated exercise
Merge pull request #42268 from petercollingridge/shaded-area-fix

Shaded area fix
Close var element properly
Merge pull request #42373 from petercollingridge/comb-like-terms-fix

Close var element properly
Fix hint for denominator of -1
Merge branch 'comb-like-terms-fix'
Merge pull request #42386 from petercollingridge/rat-expr-fix

Rat expr fix
Fix unanswerable complex numbers exercises

fix #42389; fix #42381; fix #42377; fix #42376; fix #42371; fix #42369;
fix #42366; fix #42362; fix #42360; fix #42357; fix #42355; fix #42352;
fix #42347; fix #42338; fix #42335; fix #42328; fix #42315; fix #42311;
fix #42306; fix #42303; fix #42297; fix #42295; fix #42293; fix #42292;
fix #42287; fix #42284; fix #42275; fix #42274; fix #42270; fix #42323;
fix #42329; fix #42322; fix #42390; fix #42368; fix #42348; fix #42336;
fix #42331; fix #42300; fix #42288; fix #42286; fix #42330; fix #42308;
fix #42289

Test plan: Test the following seeds locally:
http://localhost:8000/exercises/multiplying_and_dividing_complex_number_polar_forms.html?seed=120&problem=multiply-cplx&debug
http://localhost:8000/exercises/multiplying_and_dividing_complex_number_polar_forms.html?seed=79&problem=divide-cplx&debug
http://localhost:8000/exercises/powers_of_complex_numbers_1.html?debug&problem=0&seed=180

Auditors: cbhl
Reinitialize constructions after each problem

Test plan: Do a few problems in local mode and note the KhanUtil.construction gets reset after each problem

Auditors: cbhl
Allow packing of many files in one pack.rb invocation.

Summary:
In doing timing tests, I noticed that the cost of all the 'requires'
is dominating the cost of packing, when I run in the mode where I
invoke pack.rb separately on every input.  This makes it possible to
run pack.rb on many input files at once, while keeping its streaming
nature.  Basically, if multiple files are passed in, each will be
processed individually and emitted to stdout.  We can split the output
because each file ends with a /html tag.

(I wanted to use </html> to delimit files in the input as well, but I
can't because not all exercises have </html>!  They all have
<!DOCTYPE>, though, so I use that to split intead.)

A few style updates based on review.

Final style cleanups.

Test Plan:
Ran both:
   ruby build/pack.rb exercises/absolute_value_of_complex_numbers.html exercises/absolute_value.html | ruby build/pack.rb
   cat exercises/absolute_value_of_complex_numbers.html exercises/absolute_value.html | ruby build/pack.rb
and confirmed the output matches what we had for those two files
before the change, and that the two invocations produce identical output.

Reviewers: eater, alpert

Reviewed By: alpert

CC: alpert

Differential Revision: http://phabricator.khanacademy.org/D2081
Use Array.join() rather than String.+ to create file contents.

Summary:
It's much faster.

Stop ruby from doing worthless cleanup right before it exits.

Well, we do need *one* bit of cleanup before exiting...

Test Plan:
Ran
   ruby build/pack.rb ~/khan/stable/khan-exercises/exercises/division_*.html
both before and after the change, and verified there are no diffs.

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D2090
Upgrade qtip plugin for jQuery.

Resolves "jQuery.browser is deprecated" message when you hover over "Acceptable
formats".

Test Plan:
Hover over Acceptable Formats in Square Roots 2, locally, Chrome/OS X

Auditors: eater, alpert
make startLoadingExercise available to the outside via Khan so that assessments can access the promise of the exercise html file having been loaded

Test Plan:
go to an assessment
add breakpoint in makeProblem
make sure that the old problem isn't shown yet

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D2089