Add _.exclude(object, *keys)

Return a copy of the object, filtered to exclude the blacklisted keys (or array
of valid keys).

Similar to _.pick, but using blacklisting instead of whitelisting which can be
more appropriate in some cases.
Added default every/all iterator as _.identity for consistency with any/some
Unreference wrapped function in _.once

Assuming we'll never run the wrapped function again on _.once(), we can
assign null to the `func` variable, so function (and all its inherited
scopes) may be collected by GC if needed.
Tweak _.toArray.

* Combine _.isArray and _.isArguments type checks.
* _.isFunction will suffice for obj.toArray.
Document `take` alias.
Merge pull request #707 from braddunbar/take

Document `take` alias.
Merge pull request #706 from braddunbar/toarray

Tweak _.toArray.
Merge #565 from @bmaland.
Rename _.exclude as _.omit and tweak a bit.
Fix #715 - `omit` includes prototype properties.
Merge pull request #716 from braddunbar/omit-proto-props

Fix #715 - `omit` includes prototype properties.
Fixes #717 -- refactor pick and omit...
_.omit uses _.include instead of delete.
Merge pull request #719 from braddunbar/omit-include

_.omit uses _.include instead of delete.
added "drop" alias for "rest"
Adding an _.pairs function.
Merge branch 'master' of github.com:documentcloud/underscore
Changed _.zipObject to _.object, now able to handle both key and value lists, as well as a list of tuples. Works as the inverse of _.pairs
Merge pull request #720 from taiju/add-alias-drop

added "drop" alias for "rest"
Fixes #653, _.size(arguments)