Mark no input as empty instead of wrong for geometry proofs 1
Mark no input as empty instead of wrong for geometry proofs intro
Fix unstyled MathJax/Katex hint for geometry intro shared problem
Add flag in sorter object to test if user has attempted to move numbers
Check answer only if tile has been dragged, otherwise count as empty
Put change for Trello Request: Fix triangle proofs exercises to grade the initial selection as "empty" rather than "wrong"
Add zero as a base to questions
Remove debugging
compress.py has moved (in webapp)

Summary: Will check this in right after D4706

Test Plan: Fingers crossed.

Reviewers: desmond

CC: alpert

Differential Revision: http://phabricator.khanacademy.org/D4728
recognize empty check for answer type primeFactorization: fix #93217
Make bounding of MovablePoint optional; fix #92677

The congruency_postulates exercise draws the triangle in such a way that it might be off-screen, then once it's drawn it translates it so it's visible. By forcing the movablePoints to be onscreen at all times, the triangles were sometimes being drawn slightly misshapen leading to an unanswerable question. Since it's okay if some of the points are off-screen as the user drags it around (as long as some of the triangle remains on screen, which is already handled properly) I added an option to disable bounding the point.

I also removed references to the old "fixed" property in MovablePoint since it has been replaced by "constraints.fixed".

Test plan: Ensure that http://localhost:8000/exercises/congruency_postulates.html?seed=36&problem=0&debug is answerable. Also `awk fixed:` to verify that the `fixed` property of movablePoint isn't used anywhere (everything use constraints.fixed)

Auditors: jack
Add positive numbers to exercise
Fix validator
Change probabilities of questions
Rewrite hints for Fractions C&C 1
Rewrite hints for Fractions C&C 2
Switch to using expression editor
Function to return a string that can be parsed by the expression editor
Remove unnecessary fake answers
Switch to using expression editor for multiplying polynomials