best constant bug with -c fixed
is_learn is always true here (line 495 checks it)
vm["loss_function"] is always defined, and its default is "squared" (line 563).
Moreover, value "squaredloss" does not correspond to any current implementation.
using v_array.size() makes code more readable
v_array has overloaded [], so the code can be shorter
fixes to new_mf
shorter
Model movielens.reg should be inside models/ so it is ignored by .gitignore
vw -b 32 does not work

This should solve issue #450.
Not only --invert_hash, but also -f produces an empty model (even on machines with 256GB RAM).
I am not aware of application needing 32 bits hash (once -b 29 gave me the best results).
However, some users try to use -b 32, so we should produce a clear error message.
Merge pull request #452 from trufanov-nok/master

best constant bug with -c fixed
Merge pull request #454 from jhofman/master

fixes to new_mf
Merge pull request #455 from martinpopel/cleanercode

Cleaner code
Merge pull request #456 from martinpopel/issue450

vw -b 32 does not work