Thread safe changes
Convert p4Polar_ and p4Cartesian_ to atomic pointers; re-factor code accordingly
Convert all (*) to use load/store
Adjust HLTReco build file to link against Candidate library
Re-factor code to be more efficient with memory order calls
Invoke cachePolar earlier to prevent uninitialized p4Polar_
Add ioread
Fix issue with p4Cartesian_ assignment
Fix typo
properly initialize p4Cartesian_ pointer
Merge pull request #1129 from vkuznet/ThreadSafe_DataFormatsCandidate

Multithreading fixes -- Thread safe changes for Particle class.