Renamed macros {un,}likely to iRRAM_{un,}likely to avoid pollution of users' namespace.
Removed global import of std::string and std::setw in lib.h.
More robust macro definitions.
Added missing imports for std::string and std::setw to examples.
reverted single_valued::single_valued() to take no argument again, usage: 'single_valued code;'
Moved last users of stiff_{begin,end}() to use iRRAM::stiff instead.