Remove old qmake project files.

core/core.pro

@@ -1,43 +0,0 @@
-#-------------------------------------------------
-#
-# Project created by QtCreator 2017-02-26T10:51:14
-#
-#-------------------------------------------------
-
-QT       -= gui
-
-TARGET = core
-TEMPLATE = lib
-CONFIG += staticlib
-
-! include( ../common.pri ) {
-error( "Couldn't find the common.pri file!" )
-}
-
-# You can also make your code fail to compile if you use deprecated APIs.
-# In order to do so, uncomment the following line.
-# You can also select to disable deprecated APIs only up to a certain version of Qt.
-#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
-
-SOURCES += my_boost_assert_handler.cpp \
-    SqlLexer.cpp \
-    CsvWriter.cpp \
-    BackupFormatModel.cpp \
-    ExplainTreeModelItem.cpp \
-    jsoncpp.cpp
-
-HEADERS += \
-    SqlLexer.h \
-    ScopeGuard.h \
-    CsvWriter.h \
-    BackupFormatModel.h \
-	Expected.h \
-    ExplainTreeModelItem.h \
-    json/json.h \
-    std_utils.h \
-    IntegerRange.h
-	
-unix {
-    target.path = /usr/lib
-    INSTALLS += target
-}