Switch to KDE code style, use clang-format, apply for core library

.clang-format

src/charts/tchartitem.cpp

src/dialogs/tlevelcreatoritem.cpp

src/dialogs/tlevelselector.cpp

src/dialogs/ttunerdialogitem.cpp

src/libs/core/Android/tandroid.cpp

src/libs/core/Android/tandroid.h

src/libs/core/Android/tfiledialog.cpp

src/libs/core/Android/tfiledialog.h

src/libs/core/checktime.h

src/libs/core/exam/tattempt.cpp

src/libs/core/exam/tattempt.h

src/libs/core/exam/texam.cpp

src/libs/core/exam/texam.h

src/libs/core/exam/textrans.h

src/libs/core/exam/tlevel.cpp

src/libs/core/exam/tlevel.h

src/libs/core/exam/tqagroup.cpp

src/libs/core/exam/tqagroup.h

src/libs/core/exam/tqatype.cpp