Add better method names for Troposphere objects. (#1169)
Add better method names for Troposphere objects. (#1169)

* Add better method names for Troposphere objects.
   Some method names are misleading: template.add_metadata() actually
   replaces the metadata with the newly given data.
* Add deprecation warnings on old usage

cloudtools/troposphere,johnctitus/troposphere,johnctitus/troposphere,ikben/troposphere,ikben/troposphere,cloudtools/troposphere