Brainflow

Changes in this release:

* add KNN classifier for concentration and relaxation
* fix 86

[Info about this version](https://brainflow.ai/2020-08-19-new-minor-version/)

Changes in this release:

* Fix java package on Linux
* Add type checks for Julia and type hints for Python
* Fix bug in File Streamer on Windows with full paths
* Move to Ubuntu 18.04 in Travis CI
* Add docs for integration with Unreal Engine

Changes in this release:

* **Fix bug in parsing code for Cyton Daisy**
* Add *detrend* method
* Add *get_psd_welch* and *get_log_psd_welch* methods

Changes:

* Experimental: Add support for Android for OpenBCI WIFI Shield and BrainFlow Synthetic Board. We will add Android support for more devices in next releases.
* Link all precompiled third party libraries manually in runtime, it will make entire system more robust and modular
* Improved docs for Unity Integration. Detailed instructions for other game engines will be added in next releases.
* Now OpenBCI WIFI shield can be autodiscovered, even if it’s connected to a local network. You don’t have to provide IP address
* Fix Serial Port bug on Windows

Changes for BrainFlow developers:

* There is no brainflow_boards.json anymore, this code was moved to header file
* Improved docs for adding new boards


[More Info](https://brainflow.ai/2020-07-14-new-minor-version/)

Changes in this release:

* Add methods to calculate PSD and band power
* Add window for FFT - breaking change, one new argument
* Refactor enums - breaking change for C++ users, all constants should use enum class now
* Fix streaming board on multinode