Create us-mo-st_louis_county.json

This is for St Louis County, not the independent City of St Louis, and does not include any address in us-mo-st_louis.json.
Fixed json errors

Need to validate
Added missing quote mark on line 5

Passed JSONLint
Merge remote-tracking branch 'upstream/master'
Merge pull request #741 from OpenDataSTL/master

Create us-mo-st_louis_county.json - Pass JSONLint and TravisCI