Switch from nomnom to commander (#1496)

* Switch from nomnom to commander

* Fix #1489
* --macro repeatable option replaced with single --macros option with ";"
  separator (until https://github.com/tj/commander.js/issues/674)
* Add missing --max-expand option
* Replace expired --unicode-text-in-math-mode option with --strict
  (https://github.com/Khan/KaTeX/issues/1483#issuecomment-405108291)
* Add instructions for how to run in the opening comments
* Clean up option doc strings

* Implement @ylemkimon's comments

* Fix try/const bug

* Fix use of --selenium-ip

It was a quirk that --seleniumIP worked.  --help lists --selenium-ip.

* Implement comments, restore --macro repeatable argument

* Cleanup

* Restore 0 default for maxExpand

* Fix more comments from @ylemkimon

* npm run dist -> npm run build

In preparation for #1500

* Fix line length error

test/symgroups.js

@@ -4,12 +4,10 @@
 const fs = require("fs");
 const childProcess = require("child_process");
 
-const opts = require("nomnom")
-    .option("spacing", {
-        flag: true,
-        help: "Print mismatches involving spacing commands",
-    })
-    .parse();
+const opts = require("commander")
+    .option("-s, --spacing",
+        "Print mismatches involving spacing commands")
+    .parse(process.argv);
 
 const symbols = require("../src/symbols");
 const keys = Object.keys(symbols.math);