Merge branch 'sim-rat-exp' of https://github.com/petercollingridge/khan-exercises into petercollingridge-sim-rat-exp
Use %(name)s instead of %s everywhere within $._().

Summary:
%s has been deprecated for a while now, but these slipped through.

One more file I fixed up %s for.

Test Plan:
In the khan-exercises rootdir ran
   python -cSimpleHTTPServer
and visited
   http://localhost:8000/exercises/factoring_difference_of_squares_1.html
and clicked on the hint button until there were no more hints, and
verified it all showed up correctly, without %s's.

I also ran 'make exercises' in khan-root, which might possibly verify
I didn't introduce any javascript errors.

Reviewers: john, alpert

Reviewed By: john

Differential Revision: http://phabricator.khanacademy.org/D2157
Bring in new version of i18n.js and Jed.js. Remove %s-usage in a number of util files.
Redo rational expression module
Merge remote-tracking branch 'upstream/master'
Add exercises to plurals
Use plural exercises in arith word problems
Make hints more consistent
Fix to use new randRangeUnique

randRangeUnique was return an index out of range

Test plan: run exercise a few times and make sure the question isn't undefined.

fix #45048 and many others

auditors chbl, eater
Merge pull request #45051 from petercollingridge/push-ups

Add exercises to plurals
Fix geometry_proofs_1 not showing problems

fix #45045; fix #45040; fix #45039; fix #45025; fix #45015; fix #44994;
fix #44986; fix #44983; fix #44965; fix #44964; fix #44938; fix #44916;
fix #44910; fix #44902; fix #44798; fix #44659

Test plan: Load geometry_proofs_1 locally, note javascript errors. Discovered this was happening when randRangeUnique was returning the upper bound, which it didn't use to do. After then change of decrementing the lower bound, exercise loaded fine locally.

Auditors: alpert
Reset exercises back to their original state.
Merging with master.
Re-run the exercises through the updated cleaner.
Resolve merge conflict with master.
Revert a bunch of accidental merge changes.
Remove whitespace accidentally inserted by an old insertion of isMale().
Don't insert 1 for singular and fix problem with singular and identical strings being identical in some cases.
Fix handling of pluralTex to wrap the var nodes with code nodes.
Add in support for handling an() and An() methods. Fix a few exercises that were using those methods with custom strings to not do that.