Remove Src Type from Loggregator Log Messages

Signed-off-by: John Tuley <jtuley@pivotallabs.com>
refactored ParamsMap to generic.Map
add goyaml
refactored api.applications and command.push to use AppParams
push reads manifest files

The application name argument is now optional if it is present in the manifest file.

[finishes #58850876]
Hide manifest support behind feature flag CF_MANIFEST
automatically set CF_MANIFEST=true in bin/test
Changing default value for push -i from -1 to empty string

[Finishes #62723370]
Add interface for enumerating generic.Map
Adds tests for parsing single app attributes

* memory
* instance count
* hostname
* domain
* stack
* buildpack
* command

[Finishes #62429132, #62429166, #62429184, #62429196, #62429286, #62429304, #62429334]
whitelist and clean up app keys for update and create
on push, use path from manifest file
[finishes #62429256]
Connect to loggregator before starting an app

[Finishes #62677932]
Merge branch 'remove_src_type'
[finishes #62648082]
remove an unused generic function
Add support for global and local env vars in manifests

[Finishes #58850912]
Include host, domain in whitelisted app params

[Finishes #62429184, #62429196]
Fail if scale doesn't receive -i or -m flags

[Finishes #62817604]'
push command should ignore null values from manifests

[Finishes #62812064]
gcf push respects multiple apps in a manifest

[finishes #58850888]