Update build step for KaTeX.

vendor/assets/javascripts/katex.js

@@ -35,8 +35,10 @@
  1. Clone KaTeX. Anything later than 4fb9445a9 (is merged into master) will do.
  2. make (requires node)
- 3. sed -i 's,fonts/,,' build/katex.css
- 4. Copy build/katex.js, build/katex.css and fonts/* to gitlab.
+ 3. sed -e 's,fonts/,,' -e 's/url\(([^)]*)\)/url(font-path\1)/g' build/katex.css > build/katex.scss
+ 4. Copy build/katex.js to gitlab/vendor/assets/javascripts/katex.js,
+    build/katex.scss to gitlab/vendor/assets/stylesheets/katex.scss and
+    fonts/* to gitlab/vendor/assets/fonts/.
 */
 (function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.katex = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){

vendor/assets/stylesheets/katex.scss

@@ -35,8 +35,10 @@ SOFTWARE.
  1. Clone KaTeX. Anything later than 4fb9445a9 (is merged into master) will do.
  2. make (requires node)
- 3. sed -i 's,fonts/,,' build/katex.css
- 4. Copy build/katex.js, build/katex.css and fonts/* to gitlab.
+ 3. sed -e 's,fonts/,,' -e 's/url\(([^)]*)\)/url(font-path\1)/g' build/katex.css > build/katex.scss
+ 4. Copy build/katex.js to gitlab/vendor/assets/javascripts/katex.js,
+    build/katex.scss to gitlab/vendor/assets/stylesheets/katex.scss and
+    fonts/* to gitlab/vendor/assets/fonts/.
 */
 @font-face {