Add Support for Hubspot Academy

[MHM5000]

I ran the update command, but it updated to 2016.5.30.2.

• I've verified and I assure that I'm running youtube-dl 2016.5.30.2
• At least skimmed through README and most notably FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones
• Bug report (encountered problems with youtube-dl)
• Site support request (request for adding support for a new site)

➜  ~ youtube-dl -v http://academy.hubspot.com/ic16/essentials-of-an-effective-inbound-strategy
[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'-v', u'http://academy.hubspot.com/ic16/essentials-of-an-effective-inbound-strategy']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2016.05.30.2
[debug] Python version 2.7.10 - Linux-4.2.0-36-generic-x86_64-with-Ubuntu-15.10-wily
[debug] exe versions: ffmpeg 2.7.6-0ubuntu0.15.10.1, ffprobe 2.7.6-0ubuntu0.15.10.1
[debug] Proxy map: {}
[generic] essentials-of-an-effective-inbound-strategy: Requesting header
WARNING: Falling back on generic information extractor.
[generic] essentials-of-an-effective-inbound-strategy: Downloading webpage
[generic] essentials-of-an-effective-inbound-strategy: Extracting information
[Wistia] 87h8tffa9w: Downloading JSON metadata
ERROR: Error while getting the playlist
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/youtube_dl/YoutubeDL.py", line 676, in extract_info
    ie_result = ie.extract(url)
  File "/usr/local/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 341, in extract
    return self._real_extract(url)
  File "/usr/local/lib/python2.7/dist-packages/youtube_dl/extractor/wistia.py", line 49, in _real_extract
    'Error while getting the playlist', expected=True)
ExtractorError: Error while getting the playlist

I've tested this in 2 countries...