Docker 'parameters' constrained to single value per key

[LLParse]

map[string, string] doesn't work in this case because many docker parameters may be passed in multiple times. list(tuple(string, string)) or map[string, list(string)] would fix

For example: docker run --rm -P -e HEAP_MIN=512M -e HEAP_MAX=1G -e OTHEROPTS=blah blah/java_app

https://github.com/mesosphere/marathon/blob/master/src/main/scala/mesosphere/marathon/api/v2/json/Formats.scala#L167

[ConnorDoyle]

You're right, this was an oversight in the implementation.

[tnachen]

+1 we need to get this fixed for a number of folks

[ConnorDoyle]

Submitted PR #1003.