fixed Bug 1667 - models library doc does not build
fixed Bug 1660 - Handover at certain subframe produces longer delay
Adding .gitignore
point-to-point: Add support of PPP->Ethernet and Ethernet->PPP frame type conversion for CCNx protocol

point-to-point: Adding support for CCNx payload in PppHeader::Print method
topology-read: Several extensions of TopologyReader
topology-read: TopologyReader and derivatives are no longer Objects

To allow smart pointers, TopologyReader is just inherited from
SimpleRefCount<TopologyReader> class
topology-read: Making default constructor for TopologyReader::Link public.

This is necessary for some STL containers operations.
core: Small extension of Vector class (math operations)
core: Adding `inline` specifiers for DoMakeAttributeAccessor (there was a strange duplicate symbols error using apple compiler...)
visualizer: Adding plugin to display a CCNx FIB state
visualizer: Making a periodic topology rescan
internet: A new templated static method Ipv(4|6)RoutingHelper::GetRouting that allows search for any routing protocol

Examples:
Ptr<Ipv4RoutingProtocol> ptr = ...

...

Ptr<Ipv4StaticRouting> sr = Ipv4RoutingHelper::GetRouting<Ipv4StaticRouting> (ptr);
network: Adding Read (Buffer::Iterator start, uint32_t size) and PeakU8 methods to ns3::Buffer::Iterator class
point-to-point, netanim: Adding ChannelID to PointToPointChannel trace
point-to-point: Add experimental support for random losses
point-to-point: Making loss (again) independent on packet type
core: Add disclaimer note in README
core: Give ability to generate subset of documentation by utils/print-introspected-doxygen
visualizer+ndnSIM: Correcting ccnx_fib plugin
visualizer+ndnSIM: repairing ccnx_fib plugin