Create journal-of-medical-internet-research.csl

This is based on the "national-library-of-medicine-grant.csl" document.
I changed the format of the Journal name.

When installing the style in Firerox, the following line created a problem since "verfügbar" cannot be recognized. I removed the following code.

```
 <locale xml:lang="de">
    <terms>
      <term name="retrieved">verfügbar</term>
      <term name="from">unter</term>
    </terms>
  </locale>
```

The new code was validated on  http://simonster.github.com/csl-validator.js/.
I also ran it on MS Word and provided a result matching the format required by JMIR.

I will report any relevant issues to the Forum.