Agent responds to get_task

Signed-off-by: Jesse Zhang <jz@pivotallabs.com>
Signed-off-by: Damien Le Berrigaud <damien@pivotallabs.com>
Prefer single quotes for uninterpolated strings

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Introduce PublicStemcell

Encapuslates the properties and behaviour associated with a public stemcell from the perspective of the CLI
Introduce PublicStemcellIndex

Encapuslates interaction with the public stemcell index
Introduce DownloadWithProgress

Downloads a file to the current directory, reporting progress along the way
Introduce PublicStemcellPresenter

Encapsulates public stemcell ux independantly of the cli
Extracted JobTemplateLoader from ConfigurationHasher

 * Cleaned up ConfigurationHasher tests but left functionally consistent

Signed-off-by: Jeffrey Peckham <peckham@pivotallabs.com>
Extract JobTemplateRenderer from ConfigurationHasher

Signed-off-by: Nick Wade <nwade@pivotallabs.com>
Updated agent to always execute an action in the message bus handler

Signed-off-by: Damien Le Berrigaud <damien@pivotallabs.com>
Agent responds to `get_state`

Signed-off-by: Damien Le Berrigaud <damien@pivotallabs.com>
Exception is its own type; exception has message

because exception and value are mutually exclusive.

Signed-off-by: Damien Le Berrigaud <damien@pivotallabs.com>
Agent responds with exception on unknown request

behavior parity with the ruby agent

Signed-off-by: Damien Le Berrigaud <damien@pivotallabs.com>
convert double to structs for cleaner assertions

Signed-off-by: Nick Wade <nwade@pivotallabs.com>
extract JobInstanceRenderer from ConfigurationHasher

Signed-off-by: Nick Wade <nwade@pivotallabs.com>
Inject public stemcell index into presenter

Signed-off-by: Tony Hansmann <thansmann@pivotallabs.com>
Wire in new, tested, public stemcells presenter and index

Signed-off-by: Tony Hansmann <thansmann@pivotallabs.com>