Put EDAnalyzer SiPixelLorentzAngle in namespace

There is already an EventSetup product named SiPixelLorentzAngle
therefore this EDAnalyzer conflicts with it. Putting the EDAnalyzer
in a namespace solves the problem.
Also did some minor technical modifications to aid maintenance.
Merge pull request #2848 from Dr15Jones/putSiPixelLorentzAngleAnalyzerInNamespace

CalibTracker/SiPixelLorentzAngle -- Put EDAnalyzer SiPixelLorentzAngle in namespace