v0.5.0-rc4

Changes from previous RC:

• Fix GCE driver requiring manual intervention during creation (previously required manual interaction and now requires gcloud auth login to be run before docker-machine create)
• Fix some small issues around virtualization detection
• Add SUSE provisioners
• cmd (Windows) shell hint improvements
• Add bash completion and helper scripts
• Modify plugin server teardown process to be more reliable (heartbeat-based)
• Support upgrading boot2docker from custom URLs
• Various fixes around certificate regeneration

Checksums:

sha256 docker-machine_darwin-386.zip               61b38c132f169c139d5d9c58899a7e00b8f39d71c2faf1fd5c18cb89d4b1e209
md5 docker-machine_darwin-386.zip                  76dbe81ee0d6eadf3e8cf80a904f3064
sha256 docker-machine_darwin-amd64.zip             9fa7921dea8e4b9825a284141e70b94f9c558e13a6d19331059647a996005a85
md5 docker-machine_darwin-amd64.zip                4e5bd9e5e12c7c8b3b004cb056ca720e
sha256 docker-machine_linux-386.zip                823606b3841e2c436ef1d8d3f906a08e121be406509d9d6e5a49ab0012d19ea2
md5 docker-machine_linux-386.zip                   39103de853602c758af6557cdc15bef8
sha256 docker-machine_linux-amd64.zip              df85e2bcbef34b6f5db1be63ae595c7d0d54bf4688dec8e2597c59206f85e483
md5 docker-machine_linux-amd64.zip                 f56edd7cbc4b4da7cfcf7d3896cff746
sha256 docker-machine_windows-386.zip              438feddb85ed934900cd372986c82f80bd600f9c97e25379b6c15453c0645958
md5 docker-machine_windows-386.zip                 f72c24bc49b85d96b283b11bfdddae79
sha256 docker-machine_windows-amd64.zip            4eafa9ab19ec1097304812956c47db71477dd6b5b86c5c325d80e6e55f35472a
md5 docker-machine_windows-amd64.zip               6c9cb86f9f475645e48c956bf3178fb9