Allow to use different API source (Lomadee)

The base URL was:

[env].buscape.com/service/[method]/[app_id]/?[parameter]=[value]

Now it is:

[env].buscape.com/service/[method]/[api]/[app_id]/?[parameter]=[value]

The api parameter is optional.
Merge pull request #2 from RafaelMCarvalho/patch-1

Allow to use different API source (Lomadee)