implement obtain raw request functions

[e.mortoray]

In support of the raw/rendered handling this is to implement the raw request functions.

There should be two functions:

GetClickRequest
GetSubmitFormRequest

Which return a currently opaque request object. To obtain this request use the function

GetRequest

(A GotoRequest could also be introduced)

These function should be supported in all the backends where it makes sense (HTMLUnit, Selenium)

[e.mortoray (e-mortoray)]

Examples for use would be like below.

set %Request% as GetClickRequest link:My Button
GetRequest %Request%

set %Request% as GetSubmitFormRequest with
  %Params:a% value
  %Params:b% value
end
GetRequest %Request%

The results of GetRequest are then like RawGetURL.

Another feature would allow for introspection on the %Request% object itself.

[e.mortoray (e-mortoray)]

Functions implemented. As well as the introspection function "InspectRequest" (needed to test the form variant).