Extract Core::TextFile from TextEditor::BaseTextDocument.

Use it in BaseTextEditor and Designer to preserve CRLF
of the files.

Task-number: QTCREATORBUG-5901
Change-Id: I7599ce78649a3b09f2e5118d02f8cbf3db27ed31
Reviewed-on: http://codereview.qt.nokia.com/3591
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

src/plugins/coreplugin/coreplugin.pro

@@ -91,7 +91,8 @@ SOURCES += mainwindow.cpp \
     mimetypemagicdialog.cpp \
     mimetypesettings.cpp \
     dialogs/promptoverwritedialog.cpp \
-    fileutils.cpp
+    fileutils.cpp \
+    textfile.cpp
 
 HEADERS += mainwindow.h \
     editmode.h \
@@ -185,7 +186,8 @@ HEADERS += mainwindow.h \
     mimetypesettings.h \
     dialogs/promptoverwritedialog.h \
     fileutils.h \
-    externaltoolmanager.h
+    externaltoolmanager.h \
+    textfile.h
 
 FORMS += dialogs/newdialog.ui \
     actionmanager/commandmappings.ui \