Revision control

++ QtSerialPort 5.6 introduces a few new features and improvements as well as
++ bugfixes over the 5.5.x series. For more details, refer to the online
++ documentation included in this distribution. The documentation is also available
++ online:
++
++
++ The QtSerialPort version 5.6 series is binary compatible with the 5.5.x series.
++ Applications compiled for 5.5 will continue to run with 5.6.
++
++ Some of the changes listed in this file include issue tracking numbers
++ corresponding to tasks in the Qt Bug Tracker:
++
++
++ Each of these identifiers can be entered in the bug tracker to obtain more
++ information about a particular change.
++
++ ****************************************************************************
++ * Library *
++ ****************************************************************************
++
++ - Improved the documentation:
++ * [QTBUG-45391] Fixed the examples link.
++ * [QTBUG-43810] Improved the references to the readyRead() signal for
++ some examples.
++ * [QTBUG-48736] Fixed the examplesinstallpath variable in .qdocconf file.
++ * [QTBUG-44994] Fixed warning about supported directions on Windows(CE).
++
++ - QSerialPortInfo:
++ * Added enumeration of virtual tty0tty devices, which are provided by the
++ * Fixed detection of 8250 serial port types with the udev backend.
++ * [QTBUG-50223] Now it enumerates the ttyTHSx devices, which are provided
++ by the 'Tegra Jetson TK1' board, when no udev or sysfs backends are
++ available.
++
++ - QSerialPort:
++ * Added handling of the ERROR_PATH_NOT_FOUND error code on Windows, which
++ now is interpreted as QSP::DeviceNotFoundError.
++ * Fixed the QSP::clear() method that caused "The parameter is incorrect"
++ error on Windows.
++ * [QTBUG-48094] Added support of the termios v2 feature to configure a
++ custom baud rate on Linux.
++ * Custom speed configuration for one direction is not allowed on Linux.
++ Trying to do this will lead to QSP::UnsupportedOperationError.
++ * Now any attempt to change the policy to anything else than QSP::IgnorePolicy
++ will fail with QSerialPoirt::UnsupportedOperationError.
++ * Fixed stalling of reading with the limited buffer size on *nix.
++ * Improved the console warning message when a suitable custom baud rate
++ divisor is not found.
++ * [QTBUG-50052] Fixed recursion issue that is caused because of an error
++ in QSP::close().