do not share a common build directory during the compilation process

This can be harmful because the shared library and the applications may
be built with different compilation/linkage options and may give an error.

common.pri

@@ -36,9 +36,6 @@ contains(QMAKE_PRL_CONFIG, static): QTPLUGIN += qcncodecs qjpcodecs qkrcodecs qt
 # if we can't determine, assume that it is shared
 !qt_gui_prl_found: DEFINES += QT_SHARED
 
-MOC_DIR      = ../../build
-OBJECTS_DIR  = ../../build
-UI_DIR       = ../../build
 INCLUDEPATH += ../../include
 RESOURCES    = $$PWD/wkhtmltopdf.qrc