Refactored RadioMediumObservable to RadioTransmissionObservable because of its function
Added correct RadioMediumObservable and updating in AbstractRadioMedium, DirectedGraphMedium and MRM
Added some documentation
* Fix CCA detection in Cooja in the case when the receiver swicthes on the right channel during an ongoing transmission. Always add a connection on transmission, even when the channel is not correct. Initially the connection is in a dormant state; this mimics what Cooja is doing when the receiver radio is turned off;
when the receiver is turned on and switched to the right channel, `updateSignalStrengths()` is called, and the connection starts to recieve PHY-level traffic.
* Add "channel" property for DGRM edges.
* Avoid cross-channel interference on DGRM and MRM radio mediums
It is now possible to set the RSSI while the radio is sending or when
no radiodata is received. This is now supported by all radiomediums
exept MRM. This also includes a GUI to configure the values.
like /tools/mspsim.
This is a very simple modification that affects a very large number of files in Contiki: Cooja,
/platform/cooja, Collect-view, Coffe-manager, and Cooja simulation files (.csc).
I've gone through Contiki to update all references I could find. Nevertheless, this commit will likely
break external dependencies, like saved Cooja simulation files.
