Adding docs, removing bad old code

build.py

@@ -2,6 +2,17 @@
     contents = input.read()
     cleaned_contents = contents.replace('"', '\\"').replace('\n', '')
     js_contents = '''
+/**
+ * An automatically generated file, based on interface.html.
+ * An interesting problem in web development is managing HTML
+ * code in JS files. Rather than embedding string literals and
+ * concatenating them, or some other hackish soluion,
+ * we simply convert an HTML file to a JS string. Therefore,
+ * relevant edits should be in interface.html instead.
+ *
+ * The BlockPyInterface global can be seen as a constant
+ * representation of the default interface.
+ */
 BlockPyInterface = "{interface_code}";
 '''.format(interface_code=cleaned_contents)
     output.write(js_contents)