enabled and fixed missingInclude Cppcheck warnings

[firewave]

This enables the missinInclude warning to make sure all (local) includes are provided.

[firewave]

vrplayer/dlgabout.cpp:2:0: information: Include file: "ui_dlgabout.h" not found. [missingInclude]
#include "ui_dlgabout.h"
^
vrplayer/mainwindow.cpp:2:0: information: Include file: "ui_mainwindow.h" not found. [missingInclude]
#include "ui_mainwindow.h"
^

This requires the files to be generated by Qt.

[firewave]

 xrdp/xrdp_process.c:239:46: error: Syntax Error: AST broken, 'self' doesn't have a parent. [internalAstError]
    self->session = libxrdp_init((tbus)self, self->server_trans,
                                             ^

This is caused by a typedef which is only accepted by Visual Studio. I filed https://trac.cppcheck.net/ticket/14245 about it.

[matt335672]

@firewave - thanks very much for working on this.

Please comment on #3658 if you have the time.