Bump Stan.jl and Jags.jl to v"0.1.3"

Fixed several issues that prevented Stan.jl to run on Windows. Removed
Julia upper bounds in REQUIRE for both Stan.jl and Jags.jl.
Merge pull request #1809 from goedman/metadata-v2

Bump Stan.jl and Jags.jl to v"0.1.3"