Remove Src Type from Loggregator Log Messages

Signed-off-by: John Tuley <jtuley@pivotallabs.com>
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]
Clean up params to private methods in push command

This command has been worked on a lot in the last week and we didn't
always keep a close eye on whether or not the parameters to private
functions still made sense. This commit remove some unused params
and inlines a function call that was only used in a single place,
and was only a single line.