Merge pull request #169 from hal3/master

more stride bugfixes for imperative searn, dagger now implemented, saving/loading searn working
unify csoaa driver
Merge branch 'master' of github.com:JohnLangford/vowpal_wabbit
cut dead code
Merge pull request #170 from hal3/master

updated driver for imperative searn
added init_driver routine, fixed bfgs backstep
setup cb init routine
minimized noop.cc
eliminated command_example() function
incorporated john's recent changes