Revision control

++ Qt 5.13 introduces many new features and improvements as well as bugfixes
++ over the 5.12.x series. For more details, refer to the online documentation
++ included in this distribution. The documentation is also available online:
++
++
++ The Qt version 5.13 series is binary compatible with the 5.12.x series.
++ Applications compiled for 5.12 will continue to run with 5.13.
++
++ 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.
++
++ ****************************************************************************
++ * QAbstractOAuth *
++ ****************************************************************************
++
++ - Added prepareRequest and sendCustomRequest methods to authenticate any
++ custom request, including custom verbs and bodies.
++
++ ****************************************************************************
++ * QOAuth1Signature *
++ ****************************************************************************
++
++ - Added customMethodString and setCustomMethodString methods to support
++ signing requests with custom methods.