Merge (a)sync code, reformat CGP.js

Best viewed with `git diff -w`.

Since CGP-sync.js and CGP-async.js are almost equal except for one
function call, merge them into a single function. While at it, reformat
CGP.js to expose a single namespace (`CGP`) which exports the symbol
`drawAll`.

Remove `alert()` and add a `console.error()` call instead. This is less
intrustive to users (who will notice a broken graph anyway) and be more
helpful for developers (who can examine the call trace in the Developer
Console.

Add `"use strict"` and use the standard four spaces as indent. Process
the script through `js-beautify` which re-indented the code and added
some spaces between operators. Replace double by single quotes for
consistency. Rename `catch(e)` to `catch(ex)` to supress a jshint
warning about IE8.