Support Unicode Binary Operators (#951)

This is the fourth in a series of PRs to give KaTeX the ability to recognize Unicode character input.

All the characters in this PR will produce `bin` atoms.

test/katex-spec.js

@@ -2633,6 +2633,10 @@ describe("Unicode", function() {
     it("should parse more relations", function() {
         expect("⊂⊃⊆⊇⊏⊐⊑⊒⊢⊣⊩⊪⊸⋈⋍⋐⋑⋔⋙⋛⋞⋟⌢⌣⩾⪆⪌⪕⪖⪯⪰⪷⪸⫅⫆").toParse();
     });
+
+    it("should parse binary operators", function() {
+        expect("±×÷∓∔∧∨∩∪≀⊎⊓⊔⊕⊖⊗⊘⊙⊚⊛⊝⊞⊟⊠⊡⊺⊻⊼⋇⋉⋊⋋⋌⋎⋏⋒⋓⩞").toParse();
+    });
 });
 
 describe("The maxSize setting", function() {