Add support for Boost ODEint integrators. Adds new build dependency on Boost.
Support the 4 Boost Runge-Kutta integrators
provide deltaMax, deltaMin and deltaMaxOverR interface directly in Worldline and Scenery for the new integrators.
change default values of deltaMin (DBL_MIN) and deltaMaxOverR (DBL_MAX).
fix bug in Torus::deltaMax().
access new integrator in Scenery from yorick
improve new integrators (initialize minimally)
allow setting abstol and reltol in new integrators
fix Worldline constructors and initializers to clone/init the IntegState when appropriate
implement non-adaptive boost steppers
store boost integrator kind in an enum instead of a string
support compiling without boost
put BOOST_CPPFLAGS in pkg-config file
put CXXFLAGS in gyoto.pc to convey -std=c++11
give access to the new integrator tuning parameters in yorick/Photon and Star
Few fixes for compilation under MacOS:
 - default value for DeltaMaxOverR is now 1. to avoid overflow which triggers SIGFPE on MacOS
 - make the "install" target phony
 - check for the availability of -rdynamic in configure
Merge branch 'master' into odeint
Merge branch 'master' into odeint
Merge branch 'master' into odeint
Merge branch 'master' into odeint

Conflicts:
	include/GyotoScenery.h
	lib/Scenery.C
	lib/Worldline.C
include <array> in GyotoWorldline.h
update configure to test for more flags to enable C++11, and to chicken out if none work.