darwin/linux interoperability

libtoolize is prefixed with a g in osx
removed named variables and make zero value features work anonymously
Merge pull request #115 from adkatrit/patch-1

darwin/linux interoperability
fixed windows build dependency
migrate weight_mask to regressor definition
migrate stride to regressor datastructure
Merge branch 'master' of github.com:JohnLangford/vowpal_wabbit
generic feature loop
remove feature loops in bfgs.cc
make loop norm use foreach_feature
dead code removal
added export_example to library exposed to c#
merge conflicts resolved