Algorithms to implement selection hypothesis for Precision Electrons

This merge request contains hypothesis Algorithms and Tools for the selection of Precision Electrons. There are 5 files including .h and .cxx 1. Trigger/TrigHypothesis/TrigEgammaHypo/src/ITrigEgammaPrecisionElectronHypoTool.h 2. Trigger/TrigHypothesis/TrigEgammaHypo/src/TrigEgammaPrecisionElectronHypoAlgMT.cxx 3. Trigger/TrigHypothesis/TrigEgammaHypo/src/TrigEgammaPrecisionElectronHypoAlgMT.h 4. Trigger/TrigHypothesis/TrigEgammaHypo/src/TrigEgammaPrecisionElectronHypoToolInc.cxx 5. Trigger/TrigHypothesis/TrigEgammaHypo/src/TrigEgammaPrecisionElectronHypoToolInc.h I know it would be a little inconvenient to make a large merge request but the files are quite interlinked. These hypoAlgs and Tools currently apply a Et cut based selection on Precision Electron, more complex hypothesis will be applied in the near future but using the same files described here, so its best to have them in the master. There will be another merge related to this to apply similar hypothesis on "mult" chains. The JIRA specific to this activity can be found here https://its.cern.ch/jira/browse/ATR-18927. Adding @fernando and @tamartin