JSON parsing / generation with jasonpp

This release has all JSON parsing and generation removed as there is a fantastic library which can do this job: jasoncpp. This is part of every distribution and very mature. Transfer is now with JSON in both directions by default. This makes this header-only library very compact.
The demos have been updated and another demo for the USBDUX board has been added measuring temperature with an LM35.

std::deque support

• Arrays can now also be exported to JSON in form of std::deque. The reason why it's deque is because that's the buffer of choice when shifting data through it with low latency.

• The std::deque is then used in the real ADS1115 demo where the ADC data is shifted through a buffer and then web clients read them. That's in compliance with REST.

first release with complete functionality and tested

Been extensively tested so I'm happy to do the 1st release of it.