Added Array created in another document test
Added support for arrays created in different document for `_.isEqual`
Removed the areArray check from the already convoluted `if` check for clarity as suggested by @jdalton
Merge pull request #1801 from dreyacosta/master

Added navigation link on sidebar for _.noop
document some things missed before
Merge pull request #1803 from akre54/doc-fixes

document some things missed before
add note to changelog about _.union and _.difference only accepting arrays
fixing unclosed tt
(re)Add _.unzip
Merge pull request #1806 from megawac/unzip

(re)Add _.unzip
Spec various chain functions and tests for #397
Minor optimization of result
Fix test linting error

(my bad)
Merge pull request #1807 from megawac/chain-imp

Spec various chain functions and avoid unnecessary .call
Merge pull request #1808 from megawac/patch-1

Fix test linting error
Fixes #1782, arrays from different frames
Merge branch 'master' of https://github.com/jashkenas/underscore