Simplify returning from forecast()

Rather than keeping track of two separate calls to `jsonify`, the conditional logic can be used to control its arguments. If the arguments or logic grow more complicated over time, they can always be captured in a variable that gets passed to `jsonify`.
Merge branch 'master' into patch-1

Conflicts:
	weather/views.py
Merge pull request #3 from asap/patch-1

Patch 1