always build query string manually and the strip out array indexes

As issue #2 points out, arrays of options are not passed to EchosNest API as you would expect. I have modified the code to allow this to work, buy building the query and then stripping out any array indexes rather that using the $http->setParameterGet function.

I know PR #3 adds workaround functionality to allow passing in a ready built query string, bypassing the options array all together, but I find this a much more intuitive way to pass in the options.