Added loading of recorded objects

Fixed support for binary buffers
Added request headers to recorded objects
Obsoleted port and reply recorded properties but kept backward compatibility
Unified request options normalisation, buffer merging, etc. for scope and recorder
Fixed disabled net access for unfiltered requests
Fixed bad header recording for objects
Minor refactoring for clarity (e.g. renaming oldRequest to oldHttpRequest to be the same as oldHttpsRequest)

This is a bigger update but things depend on each other a bit so I decided to push it as one instead of splitting it up in 4 or 5 pull requests.