Fixes in reconstruction:

Fixes in reconstruction:

1) Define in a single place (AliMUONTrack) the algorithm to be used to associate 2 tracks by comparing the position of their clusters. Update all the classes/macro using that algorithm to find the simulated track corresponding to a given reconstructed one:

AliMUONTrack:
- Change the function IsValid(...) to be able to check the reconstructibility of the track depending on the tracking algorithm
- Change the name of the function CompatibleTrack to FindCompatibleCluster that is actually what the function does
- New function Match(...) to associate, or not, 2 tracks by comparing the position of their clusters (can be used to assign MC labels to reconstructed tracks).

AliMUONRecoCheck:
- Check the track reconstructibility according to given informations about the tracking algorithm (those info can be extracted from RecoParam).
- New function FindCompatibleTrack(...) to find in the given store a track that match the given track. Matching is done by using MC labels or by comparing clusters' position.

All other classes/macros/tasks:
- use these new functionnalities

2) Additional correction:

DecodeRecoCocktail.C:
- correct the algorithm to make it working even if there are ghost tracks
- avoid accessing OCDB when not needed

MUONRecoCheck.C:
- new histograms/graphs to study the momentum resolution as a function of the momentum
- new histograms/graphs to study the cluster resolution at each chamber
- avoid loading magnetic field when not needed

AliMUONTrackLight:
- correct constructor
- avoid using magnetic field when not needed

(Philippe P.)