Merge pull request #223 from arielf/master

New option: --progress <arg> with dual meaning
remove some header includes
Merge branch 'master' of github.com:JohnLangford/vowpal_wabbit
Initialize dump_interval for a simpler sequence of progress-update prints
Merge branch 'master' of git://github.com/JohnLangford/vowpal_wabbit
Fix --progress checkpoints to account for current example and update them accurately
bugfix: initialization of dump_interval should be outside the if (...)
clean-up old commented code
tweak some tests with --progress; add -k fo safety; refactor @AddPath
Update all test suite references to new --progress checkpoints baseline