Radio: Renamed parameter.
Radio: Replaced Register_Class with Define_Module in path loss modules.
Radio: Fixed path loss instantiation.
Radio: Added preliminary obstacle support.
Radio: Revived communication/interference range display.
Radio: Removed obsolete radioMedium.alpha and fixed renamed parameters.
Revert "AODV: renamed ModuleAccess parameters and uses getModuleFromPar()"

This reverts commit a06bb42705ed4d8143c50c379c9be6cdb14d8b48.
IdealMac: added support for NF_LINK_BREAK
IdealMac: FIXES: added destructor; lastSentPk and ackTimeoutMsg were not deleted, registered NF_LINK_BREAK signal with type IPv4Datagram.
AODV example: changed omnetpp.ini so that it works with the new Radio.
RadioMedium: added NeighborCache support.
RadioMedium: sendToNeighbors() gets non-const transmitter.
GridNeighborCache: added implementation.
NeighborListCache: added implementation.
QuadTreeNeighborCache: added implementation.
NeighborCaches & IdealMac & AODVRouting (NED): merge fixes.
NeighborCaches: removed scenario-specific default values.
NeighborCaches: added examples.
util/QuadTree: added implementation.
QuadTreeNeighborCache: separated the data structure.