Remove empty maps/interfaces from "export" manifest yaml

all empty maps and interfaces should be removed from the final manifest; also, we should remove any deprecated keys in favor of latest keys (this may mean moving maps (subtrees) from deprecated keys to the ones now in spec.

This is what we produce today:
```
application:
name: ""
namespace: ""
credential: ""
apiHost: ""
version: ""
packages: {}
package:
name: ""
version: ""
license: ""
dependencies: {}
namespace: ""
credential: ""
apiHost: ""
actions: {}
triggers: {}
feeds: {}
rules: {}
inputs: {}
sequences: {}
apis: {}
project:
name: MyFirstManagedProject
namespace: ""
credential: ""
apiHost: ""
version: ""
packages: {}
package:
name: ""
version: ""
license: ""
dependencies: {}
namespace: ""
credential: ""
apiHost: ""
actions: {}
triggers: {}
feeds: {}
rules: {}
inputs: {}
sequences: {}
apis: {}
packages:
ManagedPackage-1:
name: ManagedPackage-1
version: 0.0.2
license: ""
dependencies: {}
namespace: guest
credential: ""
apiHost: ""
actions:
HelloWorld-1:
version: 0.0.2
location: ""
function: ManagedPackage-1/HelloWorld-1.js
runtime: nodejs:6
namespace: guest/ManagedPackage-1
credential: ""
inputs:
name:
value: ""
place:
value: ""
outputs: {}
name: HelloWorld-1
exposedUrl: ""
web-export: ""
main: ""
limits: null
HelloWorld-2:
version: 0.0.2
location: ""
function: ManagedPackage-1/HelloWorld-2.js
runtime: nodejs:6
namespace: guest/ManagedPackage-1
credential: ""
inputs:
name:
value: ""
place:
value: ""
outputs: {}
name: HelloWorld-2
exposedUrl: ""
web-export: ""
main: ""
limits: null
HelloWorld-3:
version: 0.0.2
location: ""
function: ManagedPackage-1/HelloWorld-3.js
runtime: nodejs:6
namespace: guest/ManagedPackage-1
credential: ""
inputs:
name:
value: ""
place:
value: ""
outputs: {}
name: HelloWorld-3
exposedUrl: ""
web-export: ""
main: ""
limits: null
triggers:
ManagedTrigger-1:
feed: ""
namespace: guest
credential: ""
inputs: {}
name: ManagedTrigger-1
source: ""
feeds: {}
rules: {}
inputs: {}
sequences:
ManagedSequence-1:
actions: HelloWorld-1,HelloWorld-2,HelloWorld-3
ManagedSequence-2:
actions: HelloWorld-1,HelloWorld-2,HelloWorld-3
apis: {}
package:
name: ""
version: ""
license: ""
dependencies: {}
namespace: ""
credential: ""
apiHost: ""
actions: {}
triggers: {}
feeds: {}
rules: {}
inputs: {}
sequences: {}
apis: {}
filepath: ""
```