Add support for FTDI devices via D2XX API

external/libftdi1/README

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+--------------------------------------------------------------------
+libftdi version 1.5
+--------------------------------------------------------------------
+
+libftdi - A library (using libusb) to talk to FTDI's UART/FIFO chips
+including the popular bitbang mode.
+
+The following chips are supported:
+* FT230X
+- FT4232H / FT2232H
+- FT232R  / FT245R
+- FT2232L / FT2232D / FT2232C
+- FT232BM / FT245BM (and the BL/BQ variants)
+- FT8U232AM / FT8U245AM
+
+libftdi requires libusb 1.x.
+
+The AUTHORS file contains a list of all the people
+that made libftdi possible what it is today.
+
+Changes
+-------
+* Implement tc[io]flush methods & deprecate broken purge_buffers methods
+
+  Please check your code for ftdi_usb_purge_rx_buffer(),
+  ftdi_usb_purge_tx_buffer() and ftdi_usb_purge_buffers()
+  and migrate to the new ftdi_tc[io]flush() methods.
+
+  Old code will continue to function, but you'll get
+  a deprecation warning during compilation.
+
+* Add program to test buffer flush (purge) functionality
+* Add kernel driver auto attach/detach.
+  See new AUTO_DETACH_REATACH_SIO_MODULE option
+* Add ftdi_setflowctrl_xonxoff()
+* ftdi_eeprom / eeprom handling:
+  * Unify handling of all boolean eeprom flags
+  * Add device release number support
+  * Add channel_a_driver support for type xxR chips
+  * Add support for group0 drive levels on x232H chips
+  * Fix handling of high_current_drive parameter
+  * Fix inverted handling of VCP driver field for TYPE_R chips
+  * New --verbose option for eeprom decode operation
+* Add example code for async mode
+* Add SPDX license identifiers to the core library & ftdi_eeprom
+* Various python SWIG wrapper improvements
+* Various cmake file improvements
+* Fix small bugs in error code paths
+
+You'll find the newest version of libftdi at:
+https://www.intra2net.com/en/developer/libftdi
+
+
+Quick start
+-----------
+mkdir build
+cd build
+
+cmake -DCMAKE_INSTALL_PREFIX="/usr" ../
+make
+make install
+
+More verbose build instructions are in "README.build"
+
+--------------------------------------------------------------------
+www.intra2net.com                             2003-2020 Intra2net AG
+--------------------------------------------------------------------