Change of OPAL --> opal due to BoxLib (AMR)

OpalData *OPAL = OpalData::getInstance();
OpalData *opal = OpalData::getInstance();

This change applies to following files:

modified:   src/AbstractObjects/BeamSequence.cpp
modified:   src/AbstractObjects/Element.cpp
modified:   src/Main.cpp
modified:   src/Match/MatchParser.cpp
modified:   src/OpalConfigure/Configure.cpp
modified:   src/Solvers/P3MPoissonSolver.cpp
modified:   src/Structure/H5PartWrapperForPS.cpp
modified:   src/Structure/H5PartWrapperForPT.cpp
modified:   src/ValueDefinitions/RealConstant.cpp
modified:   src/ValueDefinitions/StringConstant.cpp
modified:   src/opal.cpp