Move js files into src/

Test plan:
- Make sure huxley tests, jasmine tests, make build, make metrics, make test all
  still work.

Auditors: alpert

Makefile

@@ -4,7 +4,7 @@ build: setup build/katex.min.js build/katex.min.css zip compress
 setup:
 	npm install
 
-build/katex.js: katex.js $(wildcard *.js)
+build/katex.js: katex.js $(wildcard src/*.js)
 	./node_modules/.bin/browserify $< --standalone katex > $@
 
 build/katex.min.js: build/katex.js

katex.js

@@ -6,11 +6,11 @@
  * errors in the expression, or errors in javascript handling.
  */
 
-var ParseError = require("./ParseError");
+var ParseError = require("./src/ParseError");
 
-var buildTree = require("./buildTree");
+var buildTree = require("./src/buildTree");
-var parseTree = require("./parseTree");
+var parseTree = require("./src/parseTree");
-var utils = require("./utils");
+var utils = require("./src/utils");
 
 /**
  * Parse and build an expression, and place that expression in the DOM node

metrics/replace_line.py

@@ -2,12 +2,12 @@
 
 import sys
 
-with open("../fontMetrics.js", "r") as metrics:
+with open("../src/fontMetrics.js", "r") as metrics:
     old_lines = file.readlines(metrics)
 
 replace = sys.stdin.read()
 
-with open("../fontMetrics.js", "w") as output:
+with open("../src/fontMetrics.js", "w") as output:
     for line in old_lines:
         if line.startswith("var metricMap"):
             output.write("var metricMap = ")

test/katex-spec.js

@@ -1,7 +1,7 @@
 var katex = require("../katex");
-var buildTree = require("../buildTree");
+var buildTree = require("../src/buildTree");
-var parseTree = require("../parseTree");
+var parseTree = require("../src/parseTree");
-var ParseError = require("../ParseError");
+var ParseError = require("../src/ParseError");
 
 var getBuilt = function(expr) {
     expect(expr).toBuild();