Change default behavior of keys:add to upload as key_comment if available.

This edit will default to uploading the users key as identified by its key comment if the key comment is defined, and gracefully fall back to the older method if it is not.

This should improve usability for some users working from multiple workstations.
PEP8 Formatting
Update deis.py
Updated several python packages.
Specified package version 0.6.4 for Docker, not virtual package.
Updated EC2 AMIs in all regions for security updates.
Merge pull request #289 from opdemand/236-refresh-amis

Fixed #236 -- updated EC2 AMIs in all regions for security updates.
Updated prepare-image-* scripts for minor optimizations.
Updated project version strings to 0.2.0.
Updated Ruby gems dependencies.
Switch master to v0.2.1
Full Vagrant provider. Squashed commits
Fixed Flake8 errors
Silence the McCabe checker on two methods, refs #276.
Updated Berksfile format for 3.0.0 beta 3 and Chef to 11.6.2.
Started on docs
Changed sync_folder path in Vagrantfile.local.example to mount parent path
Added missing warning to vagrant provisioning script.
Default login/register URL to http:// schema if it's not specified.
Moved "Terms" section back to top level nav in docs.