utils: fix compilation on Darwin

Although Docker daemon does not work on Darwin, the API client will have
to work. That said, I'm fixing the compilation of the package on Darwin.
Fixed typo in remote API doc
Merge pull request #644 from philspitler/master

- Documentation: Fixed typo in remote api docs
docs/remote_api: remove trunc_cmd from /containers/ps example

Apparently, this parameter does not exist anymore.
Fixed typos
Merge pull request #646 from kirang89/master

- Documentation: Fixed typos in README
Merge pull request #645 from fsouza/fix-api-docs

- Documentation: remove trunc_cmd from /containers/ps example no longer needed.
Merge pull request #639 from fsouza/fix-utils-darwin

utils: fix compilation on Darwin