Merge pull request #2464 from xillibit/k31_bugs3

Simplify a bit part of TFA check on KunenaLogin class
Regression emails aren't sent for subscribers after last changes
K3.1 J2.5.x Undefined class constant 'SCALE_FIT' in KunenaImage #2466
K3.1 Crypsis Unthankyou missing #2452
Merge pull request #2465 from xillibit/kdev-patch-4

Regression emails aren't sent for subscribers after last changes #2366
Merge pull request #2469 from xillibit/kdev-patch-6

K3.1 Crypsis Unthankyou missing #2452
Merge pull request #2467 from xillibit/kdev-patch-5

K3.1 J2.5.x Undefined class constant 'SCALE_FIT' in KunenaImage #2466
Added other constants for consistency
Merge pull request #2471 from coder4life/patch-1

Added other constants for consistency
Update KunenaLogin class to make working login with TFA