JSON Object Types

[ccoffrin]

By default JSON.parse returns Dict{UTF8String, Any} and we typically use Dict{AbstractString, Any}.

1. Figure out why a function of Dict{AbstractString, Any} cannot accpt an argument of Dict{UTF8String, Any}.

2. Migrate code to a robust solution, no types?

3. remove special type cases from JSON.parse() calls

[mlubin]

All of the string stuff is changing in 0.5

[mlubin]

(By the way, this would be a good time to test since 0.5 is in the final RC stages.)