Refactor spec helper not to duplicate configuration logic

Signed-off-by: Damien Le Berrigaud <damien@itsdamo.com>
Refactored TaskClient to be instantiated
RIntroduce dependency management to avoid usage of singletons and class methods

Signed-off-by: Damien Le Berrigaud <damien@itsdamo.com>
Merge pull request #77 from geapi/refactor_configuration

Configuration refactoring
Add custom buildpack controller that takes a tar and adds it to a custom buildpack blobstore
Inject blobstore and upload handler into the buildpack controller

Signed-off-by: Michael Fraenkel <fraenkel@us.ibm.com>