This commit adds all the missing includes when the PCH header is not used.
Also, some includes are reordered and/or made consistent (e.g. "#include <QtEndian>" -> "#include <QtCore/QtEndian>").
According to Qt's documentation the PCH header doesn't need to be included.
From https://doc.qt.io/qt-5/qmake-precompiledheaders.html:
"To make your project use precompiled headers, you only need to define the PRECOMPILED_HEADER variable in your project file."
"qmake will handle the rest, to ensure the creation and use of the precompiled header file. You do not need to include the precompiled header file in HEADERS, as qmake will do this if the configuration supports precompiled headers."
This flag allows users of AboutDialog to determine which
tab of the about dialog (About, License, Authors,
Third-party Licenses) should be active when the dialog
is first shown.
This is needed for the license command-line flags on Windows,
where qFatal() output is shown via Windows's ShowMessageDialog.
Unfortunately, both the AUTHORS file and the combined
third-party license text are too big to display in a regular
dialog.
To avoid this, we'll show the AboutDialog when --license,
--authors and --third-party-licenses are passed to Murmur
on Windows.
This commit only implements the AboutDialog-related changes
necessary to implement this.
