Create browser-only .js file evaluating application/wisp scripts.

I did the changes you suggested in #50, and found that I have to add read* to functions required by src/engine/browser.wisp to make it work.

This allows me to do something like this:
```html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Wisp</title>
    <script src="scripts/wisp.js"></script>
    <script type="application/wisp">
      (print "Wisp code run on the client in a script tag!")
    </script>
    <script type="application/wisp" src="scripts/test.wisp"></script>
  </head>
  <body>
  </body>
</html>
```

`scripts/wisp.js` being the `browser-embed.js` created by this new Makefile, and

`scripts/test.wisp` being file with contents:
```clojure
(print "Wisp code run on the client from a file!")
```

this does
```
Wisp code run on the client in a script tag!
Wisp code run on the client from a file!
```
in my console.