Plugin: BBB: Update upstream PHP API library

[ywarnier]

The version of the BigBlueButton API library for PHP we are using is old.
It looks like the latest update from upstream that we did was in 2012: c4bb8e7#diff-dc18db170228ff0de18d69389f35fa62

Wouldn't it be a good idea to merge the ~10 changes that we made since then with the new version they provide at https://github.com/bigbluebutton/bigbluebutton-api-php/blob/master/src/BigBlueButton.php ?

Also, this might be better as a composer dependency...?

[ywarnier]

At least my last change about CURL is already in their latest version.

[ywarnier]

From what I can see, only the following changes have to be checked (the last one on CURL option was already checked):

• 4b29827#diff-dc18db170228ff0de18d69389f35fa62
• c5b4291#diff-dc18db170228ff0de18d69389f35fa62
• 6b29f9c#diff-dc18db170228ff0de18d69389f35fa62 (this is a big one but the same change is repeated over and over)
• 85ef745#diff-dc18db170228ff0de18d69389f35fa62 (this one might be tricky)
• 29cc82f#diff-dc18db170228ff0de18d69389f35fa62 (long)
• c393fe0#diff-dc18db170228ff0de18d69389f35fa62 (long)
• e190df7#diff-dc18db170228ff0de18d69389f35fa62 (long and complex?)
• 0fd2cbc#diff-dc18db170228ff0de18d69389f35fa62 (just sanity check)

The rest is just code styling