Revert "remove unused GSL components; search in LHCb and ATLAS code base didn't …
…reveal any usage of them"
This reverts commit 42443573. Fixes GAUDI-1167.
Conflicts:
GaudiExamples/src/GSLTools/EqSolverIAlg.h
GaudiExamples/src/GSLTools/EqSolverPAlg.h
GaudiExamples/src/GSLTools/FuncMinimumGenAlg.h
GaudiExamples/src/GSLTools/FuncMinimumIAlg.h
GaudiExamples/src/GSLTools/FuncMinimumPAlg.h
GaudiGSL/GaudiGSL/GaudiGSL.h
GaudiGSL/GaudiGSL/GslError.h
GaudiGSL/GaudiGSL/GslErrorHandlers.h
GaudiGSL/GaudiGSL/IFuncMinimum.h
GaudiGSL/GaudiGSL/IGslErrorHandler.h
GaudiGSL/GaudiGSL/IGslSvc.h
GaudiGSL/src/Components/EqSolver.cpp
GaudiGSL/src/Components/EqSolver.h
GaudiGSL/src/Components/FuncMinimum.cpp
GaudiGSL/src/Components/FuncMinimum.h
GaudiGSL/src/Components/GslErrorCount.cpp
GaudiGSL/src/Components/GslErrorCount.h
GaudiGSL/src/Components/GslErrorException.cpp
GaudiGSL/src/Components/GslErrorException.h
GaudiGSL/src/Components/GslErrorPrint.cpp
GaudiGSL/src/Components/GslErrorPrint.h
GaudiGSL/src/Components/GslSvc.cpp
GaudiGSL/src/Components/GslSvc.h
GaudiGSL/src/Lib/GaudiGSL.cpp
GaudiGSL/src/Lib/GslErrorHandlers.cpp