Merge pull request #82 from anthonycabot/3.8

Typo fix for 3.8 (JGreen feedback)
Pimp API authentification
Merge pull request #83 from nlegoff/pimp_api_auth

[3.8] Pimp API authentication doc
Fix plugins docs
Merge pull request #84 from nlegoff/pimp_plugin

[3.8] Fix plugins docs
Fix typo in Authentification.rst