Merge pull request #304 from arielf/master

add short option -B for --bootstrap
using computed types in gd.cc
Merge branch 'master' of github.com:JohnLangford/vowpal_wabbit
something not working
more general computed types
unified updates
more update simplifications
update refactoring
compute stride once
remove spurious dependency
more refactoring of gd.cc
updated tests
fix free_flatten_example
better flatten_example and free_flatten_example
another flatten_example fix
ignore *.dSYM (darwin debug directories) and binary library/gd_mf_weights
use strerror(errno) for error reporting throughout
make the log of the communication with spanning_tree more transparent
#include <cerrno> for errno
more verbose spanning_tree error reporting and communications