Community additions to BMI

[mdpiper]

BMI specs and examples for Javascript and Julia have been created by researchers in the community. I'd like to add these to the docs. I'll create a PR soon, but I want to give everyone a heads up in case there's any discussion.

[mdpiper]

I'm thinking about adding these to a new table, titled something like Table 2: Community-contributed BMI language specifications.

[alee]

(from BMI Council meeting) Niels Drost mentioned it would be good to make the table more explicitly labelled as Community Contributed since CSDMS isn't officially supporting them

[mdpiper]

Here's the PR: #120. I added a new table to the README and the docs.

[alee]

also might be worth considering what it would take to graduate a community contributed BMI to an officially supported BMI through some incubation type process (at some point, not part of #120)