Initial conditions for Weibel instability added.
Update One_particle_Test.yaml file by output.
Clear files in the correct dirctory.
Specify color of particles in YAML file

There is a new property "color", which can be
- a color name (e.g. "red", "blue", ...)
- a HEX code (e.g. "FF77FF")
- or the keyword "random" for random color
Specify PoissonSolver in YAML file.

Possible settings are:
- fft: use PoissonSolverFFTPeriodic()
- empty: use EmptyPoissonSolver()
Merge branch 'upstream' into file

Conflicts:
	pixi/input/One_particle_Test.yaml
	pixi/input/Pair_of_particles.yaml
	pixi/input/Two_stream_instability.yaml
Merge pull request #89 from aipp/file

Specify color of particles and PoissonSolver in YAML file
The Weibel initial conitions are now changed such that the particles are initialized according to a Gaussian distribution. The instability is not yet resolved!
Merge branch from the origin to Daniil's local master.
Parameter adjusted such that the Weibel instability became observable. Wave test is work in progress.
Speed of light is now fixed to sqrt(eps0*mu0), in order to avoid inconsistency.
Error message for wrongly set speed of light added.
Bugs in CloudInCell.java, which sometimes caused runtime ArrayIndexOutOfBound errors, are fixed.
Merge pull request #90 from dgelfand/master

Weibel instability and wave test added.