v1.5 of libftdi (2020-07-07)

• 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

Full Changelog: v1.4...v1.5