newton_generic: minor layout changes
newton_generic: avoid unnecessary copy of newton_values
newton_generic: implement CommutativeConcreteLinSolver
newton_generic: speed up CommutativeDeltaGenerator
newton_generic: use templated typedefs for Newton, etc.
cmake: use -O3 and -march=native for Release mode
check_output: minor improvements
main: add a template parameter to apply_newton
improve performance of CommutativeDeltaGenerator
newton: change name of Generator2 back to Generator
Merge pull request #39 from michalt/dev

Improvements of newton_generic---very cool!