Added option for defining a custom parameter name for remote chained

I needed to specifiy a custom parameter name instead of using the select field id when doing server request with the remote chained version of the plugin.
I just use the already defined options variable and pass a parameter called paramName. Then before the remote request I check the presence of the option. If is defined use that value. Otherwise fallbacks to the field id.
I think this adds some more flexibility. I dont know about the variable name "paramName".  I dont like it that much but i couldnt think any better.