Put all application logic into Application class.

Application process message and split it into params list itself (this
prevents code duplication).
Application store params unless other components ready to process them.
Application incapsulate all QMacApplication and SessionApplication logic
(this is too small to have separate classes).

src/app/app.pri

@@ -14,20 +14,9 @@ usesystemqtsingleapplication {
     }
 }
 
-!nogui {
-    macx {
-        HEADERS += $$PWD/qmacapplication.h
-        SOURCES += $$PWD/qmacapplication.cpp
-    }
-    HEADERS += $$PWD/sessionapplication.h
-    SOURCES += $$PWD/sessionapplication.cpp
-}
-
 HEADERS += $$PWD/application.h
 SOURCES += $$PWD/application.cpp
 
-nogui: HEADERS += $$PWD/headlessloader.h
-
 unix: HEADERS += $$PWD/stacktrace.h
 strace_win {
     HEADERS += $$PWD/stacktrace_win.h