SCT_RawDataByteStreamCnv: Updating SCT_RodDecoder according to ATLAS Coding Guidelines

Updating the SCT_RodEncoder after a review of the code in light of the ATLAS Coding Guidelines (https://twiki.cern.ch/twiki/bin/viewauth/AtlasComputing/CodingGuidelines). Some related changes also made other parts of the package.

Tested with RunTier0Tests.py with release master,x86_64,slc6,gcc8,opt,2019-03-17T2152,Athena.

q221 not passed: Error related to TriggerMenu (ERROR Problems when importing TauDef.py, disabling tau chains.)

q341 passed!

See attached logfile: RunTier0Tests.log

As a part of the ATLAS Qualification Task of @krbjoerk to review the SCT ByteStreamConverter in light of the ATLAS Coding Guidelines.

Technical supervisor: @oda