This also now allows to skip events

Fix hundreds of std=c++11 compiler warningsAllow to change compiler settings in cmake/DD4hep.cmake valid for all packages.Watch out for CMAKE_CXX_FLAGS in cmake/DD4hep.cmake.Move to use Boost spirit::phoenix version 3. ---- Prepare for ROOT 6

No code changes. Common code formatting removing tabs, replacing with spaces (tab-size=-2) + emacs reformatting.

Remove debugging items from CLICSiD compact xml. First implementation of Multipole magnetic field description. Add missing units in DDG4 LCIO conversion.

 - fixed generator status: set to 0 if
   particle created in simulation

Improved version of MC particle handler, fix calorimeter hit aggregation with multiple contributions