Merge branch 'master' into develop
Replace os.getresuid() so it works on Mac OS X.
Fix path creation.
Fix gpg binary path validation.
Fix validation of --verify argument using detached sig.
Fix GPGBase._homedir_setting docstring parameter name.
Fix whitespace indentation levels in _util.InheritableProperty class.
Merge branch 'hotfix/inheritable-property-whitespace' into develop
Merge branch 'hotfix/GPGBase-homedirsetter-docstring' into develop
Merge remote-tracking branch 'drebs/bug/fix-os.getresuid-not-supported-on-os-x' into develop
Pin psutil==1.2.1 and add a SHA-256 hash for peep.

See https://pypi.python.org/pypi/peep/ for a pip wrapper which pins packages
by hash digest in a requirements.txt file.
Merge branch 'hotfix/pin-psutil-version' into develop
Fix Sphinx build failing due to missing psutil import.
Add Makefile commands for creating zipped doc builds.
Update setup.py to use dependency links from requirements.txt.
Add additional setup.cfg [upload_docs] parameters.
Merge branch 'hotfix/pin-psutil-version' into develop
Merge branch 'release/1.2.4'