Support for javascript (mozilla)

I wrote some simple bindings for javascript using the mozilla API / (see http://plindenbaum.blogspot.fr/2013/05/binding-c-library-with-javascript.html )

Example:
```javascript
load("tabix.js");

var tabix=new TabixFile("example.gtf.gz");
var iter=tabix.query("chr2:32800-35441");
while((line=iter.next())!=null)
 {
 print(line);
 }
tabix.close();
```



Added a README.md and a .gitignore