2.7.6 Weather and Airport plugins, config.json update, bugfixes

[WARNING]
Run pip3 install -r requirements.txt --upgrade to get translations working!

General:

• Default config.json edited to only load some initial plugins. This allows us to scale a lot faster with adding new plugins, as they won't all be loaded on boot

New Plugins:

• Added weather forecast.py
• Added metar.py plugin

Others:

• Updated image links to accept .jpeg files
• Slack.py will respect OTR configuration
• Small bugfixes to slackrtm.py
• bugfixes to make simplytranslate work again (requirements.txt updated!)
• Improved dice roll functions
• Bugfixes for cleverbot.py
• Added debian daemon script to examples files