Combine all unexpected commands to a single class

Source/CMakeLists.txt

Source/cmCommands.cxx

Source/cmElseCommand.cxx

Source/cmElseIfCommand.cxx

Source/cmElseIfCommand.h

Source/cmEndForEachCommand.cxx

Source/cmEndForEachCommand.h

Source/cmEndFunctionCommand.cxx

Source/cmEndFunctionCommand.h

Source/cmEndIfCommand.h

Source/cmEndMacroCommand.cxx

Source/cmEndMacroCommand.h

Source/cmEndWhileCommand.cxx

Source/cmEndWhileCommand.h

Source/cmUnexpectedCommand.cxx

Source/cmUnexpectedCommand.h

bootstrap