Prepare global Environment singleton for PMacc
Edited after review-comments

-modefied Environment.hpp
-removed most of the forward declarations for class Environment
-removed some .tpp files
Made picongpu compile with the singletons from GameofLife
Integrated more Singletons in the Environment.hpp
add ParticleFactory to Environment

- make PArticleFactory getInstance private
- use Environment<> to get instance of ParticleFactory
- sove all dependencies
- fix all example compile time errors
Merge pull request #1 from psychocoderHPC/conrad-topic-Environment-addParticleFactory

add ParticleFactory to Environment
Close #241 - fix typo
Add BG FieldJ Config and RunOneStep implementation
Add Changelog Doc for new lines in fieldBackground
Merge pull request #243 from PrometheusPi/warningsRadiation

Close #241 - radiationObserver examples
Merge branch 'topic-Environment' into topic-EnvironmentSingleton

Conflicts:
	src/libPMacc/examples/gameOfLife2D/include/GatherSlice.hpp
	src/libPMacc/examples/gameOfLife2D/include/Simulation.hpp
	src/libPMacc/include/dataManagement/DataConnector.hpp
	src/libPMacc/include/mappings/simulation/GridController.hpp
	src/libPMacc/include/simulationControl/SimulationHelper.hpp
	src/picongpu/include/fields/FieldB.tpp
	src/picongpu/include/fields/FieldE.tpp
	src/picongpu/include/fields/FieldJ.tpp
	src/picongpu/include/fields/FieldTmp.tpp
	src/picongpu/include/fields/MaxwellSolver/DirSplitting/DirSplitting.hpp
	src/picongpu/include/initialization/InitialiserController.hpp
	src/picongpu/include/initialization/SimRestartInitialiser.hpp
	src/picongpu/include/initialization/SimStartInitialiser.hpp
	src/picongpu/include/particles/Particles.tpp
	src/picongpu/include/plugins/EnergyFields.hpp
	src/picongpu/include/plugins/FieldEnergy.tpp
	src/picongpu/include/plugins/IntensityModule.hpp
	src/picongpu/include/plugins/ParticleDensity.tpp
	src/picongpu/include/plugins/ParticleSpectrum.tpp
	src/picongpu/include/plugins/hdf5/HDF5Writer.hpp
	src/picongpu/include/plugins/hdf5/WriteSpecies.hpp
	src/picongpu/include/plugins/output/GatherSlice.hpp
	src/picongpu/include/plugins/output/images/ParticleDensity.hpp
	src/picongpu/include/plugins/output/images/Visualisation.hpp
	src/picongpu/include/simulationControl/MovingWindow.hpp
	src/picongpu/include/simulationControl/MySimulation.hpp
Correct Links to Show to Mainline Repo
Correct SI Unit for Current Density in Doc String
Remove trailing _ cautioness
Plain Links Need No Brackets
Use CONTRIBUTING.md

Rename doc/PARTICIPATE.md to CONTRIBUTING.md to support
special GitHub syntax for issues and pull requests.
Merge pull request #245 from ax3l/topic-bgFieldJ

Add Background FieldJ
Set -DNO_FREETYPE to calm down headers

pngwriter.h checks even in the installed version
for the USE/NO_FREETYPE makro for depending
includes...
Merge pull request #247 from ax3l/topic-contributing

Close #242 - Use CONTRIBUTING.md
Merge pull request #248 from ax3l/fix-freetype

Set -DNO_FREETYPE to calm down headers