Ignore signal interrupts during initialization semaphore, fix timed wait.
Check success of starting each simulation, and abandon on failure.
Ensure the OscCursorInterface object is deleted.
Remove unused/unnecessary/unimplemented get_lo_server() function from OscBase.
Fix segfault bug in destruction order.

Two problems: the Simulation instances were freeing m_server before
the member OscValues were destroyed, which try to remove methods from
m_server, causing a segfault.  Solution is to manually set m_server =
0 for each OscValue member of a Simulation -- not elegant, but it
works.

Additionally, due to the order in which destructors are called,
calling stop() in ~Simulation() was not sufficient to ensure the
thread has stopped before ~InterfaceSim() et al are called.  Therefore
the thread is running and dereferencing "me" while the object is
partially destroyed.  The solution is to call stop() as early as
possible in the destruction sequence, i.e., in ~InterfaceSim() et al.
Clean up CHAI world on ~HapticsSim, but don't add cursor twice.

Cursor adds itself to the world on creation, so don't do it again.
Was causing double delete.
Re-install the SIGINT handler in case it was overridden by haptics driver.

Specifically OpenHaptics seems to do this. We are noticing a segfault
in hdDisableDevice() on Linux.
Allow to specify remote receivers in addition to local SimulationInfo destinations.

Renames SimulationInfo class to SimulationReceiver, and allows to
instantiate it with a liblo-style URL instead of a Simulation's
lo_address/queue.

Adds possibility of specifying multiple `-s' options on the command
line and following the simulation spec string with a liblo URL.

This means that if Dimple is executed on one computer with "-s v", and
on the other computer with "-s ph -s v,osc.udp://<hostname>:7773",
then the haptics and physics simulations will run on one computer, and
send visual update messages to the remote computer that displays the
graphics.
Add a command-line option to specify the listening ports.
Fix whitespace in help output.
Allow adding simulations after startup, on message /world/add_receiver.

A simulation can now be started e.g. with "-s hp", and another
instance of Dimple can be executed with
"-s v,osc.udp://<hostname>:7774", where 7774 is the Interface port,
and the first instance will use the second one for the visual
simulation.  Similar with physics or haptics.