[WIP] Do what I mean when I send a request

This is a work in progress to get DWIM functionality into the request sending. 

This is supposed to make it possible to use the command `es-execute-request-dwim` and emacs will Do The Right Thing™.  

The priority is as follows:
If there is a request header, emacs will call the query under the cursor with those parameters.
If there is no request header, emacs will call the query with the variables stored in es-mode.
If the command is prefixed with `C-u` (or any other prefix) all queries in the buffer is sent from top to bottom.