Add DDRec/src/plugins to folders documented by doxygen

Add groups for plugins and some example
Add an entry in the main "Modules" part of the doxygen website so they are easily found.
And sub groups for different plugin types.
See changes in the plugins for example. The documentation in these changes is not complete.

Clearer status message in moveToEvent functions, change verbosity for particle printout in HepMC, add comment

use m_currEvent everywhere
move skipEvent logic to moveToEvent

  as using direct access always requires runNum==0 and sequential evt nums ...

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.