Migrate to eslint

Summary
We'd like contributors to use the same linter and lint rules that we use
internally.  This diff swaps out eslint for jshint and fixes all lint failures
except for the max-len failures in the test suites.

Test Plan:
- ka-lint src
- make lint
- make test

Reviewers: emily

server.js

@@ -1,3 +1,4 @@
+/* eslint no-console:0 */
 var fs = require("fs");
 var path = require("path");
 
@@ -41,7 +42,13 @@ var serveBrowserified = function(file, standaloneName) {
 };
 
 app.get("/katex.js", serveBrowserified("./katex", "katex"));
-app.use("/test/jasmine", express["static"](path.dirname(require.resolve("jasmine-core/lib/jasmine-core/jasmine.js"))));
+app.use("/test/jasmine",
+    express["static"](
+        path.dirname(
+            require.resolve("jasmine-core/lib/jasmine-core/jasmine.js")
+        )
+    )
+);
 app.get("/test/katex-spec.js", serveBrowserified("./test/*[Ss]pec.js"));
 app.get("/contrib/auto-render/auto-render.js",
         serveBrowserified("./contrib/auto-render/auto-render",
@@ -56,7 +63,7 @@ app.get("/katex.css", function(req, res, next) {
 
         var parser = new less.Parser({
             paths: ["./static"],
-            filename: "katex.less"
+            filename: "katex.less",
         });
 
         parser.parse(data, function(err, tree) {