Thread safety cleanup in KalmanAlignmentAlgorithm

Make the return value of two const functions be
a const pointer instead of just a pointer.
Eliminates a potential thread safety problem
reported by the clang static code analyzer.
Thread safety cleanup in PhysicsToolsObjects

I first looked at this because reports of potential
thread safety problems from the static analyzer,
but a recent commit fixed those already. I added
a comment before the call to EvalPar as I spent
some time looking at it.

Also added a return statement in
PerformancePayloadFromTFormula::printFormula
when the index fails the range check instead
of trying to use it anyway.
Merge pull request #3313 from wddgit/threadSafetyKalmanAlignmentAlgorithm

Alignment/KalmanAlignmentAlgorithm -- Thread safety cleanup in KalmanAlignmentAlgorithm
Merge pull request #3334 from wddgit/threadSafetyCondFormatsPhysicsToolsObjects

Multithreading -- Thread safety cleanup in PhysicsToolsObjects
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X