improve javascript  code

**wab** appears 232 times in wab/js/main.js
It may appear only 2 or 3 times : 

``` javascript
var wab = { 
...
GEOR.Addons.wab = function(map, options) {
...
GEOR.Addons.wab.prototype
```

or if we insert "var wab=" properties in prototype : 

``` javascript
GEOR.Addons.wab = function(map, options) {
...
GEOR.Addons.wab.prototype
```
