Tracking/SkyLines: define a protocol for querying user names

The traffic list dialog now shows the user's display name instead of
the internal user id.
Computer/StatsComputer: Fix logic to handle location jumps

Once a single location jump was detected the calculation of stats never
resumed.
Tracking/SkyLines: check HAVE_SKYLINES_TRACKING_HANDLER, not HAVE_POSIX
LX/Parser: Fixed LXWP3 documentation

Source is the "Table of LX NMEA outputs" and the
"LX1600 communication protocol"
ManageLX16xxDialog: Fixed window title

The LX1600/1606 are not LXNAV products.
ManageLX16xxDialog: Set title to product name

e.g. "LX 1606" or "LX 1600"
Tracking: add macro HAVE_SKYLINES_TRACKING

Prepare for allowing SkyLines tracking without HTTP client.
Tracking: add macro HAVE_LIVETRACK24

To replace HAVE_TRACKING where only LiveTrack24.com support is being
checked.
SkyLines/Tracking: don't use HAVE_TRACKING

In Tracking/SkyLines/Features.hpp, decide whether tracking is
available without consulting HAVE_TRACKING.  HAVE_TRACKING will not be
enabled by HAVE_SKYLINES_TRACKING, not the other way round.
OS/SocketDescriptor: enable sendto()/recvfrom() on Windows CE
OS/SocketAddress: convert Port() to a static method
OS/SocketAddress: assign INADDR_ANY in MakePort4()
OS/SocketAddress: build on Windows CE

Disable the Lookup() method because getaddrinfo() is not available.
OS/SocketDescriptor: use SocketAddress::MakePort4()
OS/SocketAddress: add static method MakeIPv4Port()
Tracking/SkyLines: pass SocketAddress to Open()

Use SocketAddress::MakeIPv4Port() instead of SocketAddress::Lookup().
The former doesn't require getaddrinfo().
Tracking/SkyLines: enable on Windows CE

Our code base is finally ready to support UDP networking on Windows
CE.  Unidirectional currently, due to lack of IOThread.
Util/RadixTree: apply naming convention
Waypoints: normalise the string for SuggestNamePrefix()

Allows using lower-case letters on the hardware keyboard.
DataField/Boolean: inline GetAsBoolean()