Bump MODULE_VERSION to 5.2.1

Change-Id: I7129dbbb914ca981017375004a1da7b102640dde
Reviewed-by: Matti Paaso <matti.paaso@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I473774c5e7a62c2aa8541d22327366364ad70553
JavaScriptCore: c++11 compile fix

Change-Id: I0de4140323db25765243748dfed8533bca39217c
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>