Update Gcal implementation to v3

# Fix the `Upcoming Events` Section
> (aka The _"Thanks Google!"_ Update :rage: because:
>   1. Google broke the calendar in the first place.
>   2. Google says to use `singleEvents => false` in order to have multiple recurring events. **They lied. :rage:**
> _so pretty much, this fix could've come much sooner._

Also, you might want to take a little look for bugs, problems, and optimizations because I kind of went into _":rage:rage mode:rage:"_ after the whole `singleEvents` thing...

## Files Added/Modified
- `index.html`: Add `include` to `upcoming-events.php`.
- `upcoming-events.php`: Bulk of code
- `subtrees/google-apis`: Subtree of [`google-api-php-client`](https://github.com/google/google-api-php-client). Could be trimmed of files.
- Also, `main.js`, to change `chrome` to `Chrome` from my previous pull request #1.

Make sure to change the `$apiKey` var in `upcoming-events.php`!