Switched to normalized coordinates.
Corrected interpolation (check added comment) and disabled Unit test.
Removed boundary handling. (this is done by the grid)
Renamed to emphasize conntection to CloudInCell.
Removed chargedensity variable in the Particle class because it is no logner needed.
Merge branch 'chargeconserving-interpolator'

Conflicts:
	pixi/src/main/java/org/openpixi/pixi/ui/PoissonSolverCalculations.java
	pixi/src/test/java/org/openpixi/pixi/physics/fields/PoissonSolverTest.java
	pixi/src/test/java/org/openpixi/pixi/physics/grid/ChargeConservingAreaWeightingTest.java

* Switched to normalized coordinates like in CIC.
* Corrected the interpolation s.t. it really fulfils the continuity equation now.
* Disabled Unit Test because it was testing for the wrong thing. (this algorithm does NOT calculate (x(t)-x(t-dt)) / dt!) Check algorithm description for details.
* Removed boundary handling because this is done by the grid now. Periodic boundaries were hardcoded in the algorithm. This change might lead to a slightly higher probability of index out of bound errors.
* Removed the chargedensity variable from Particle because it is no longer needed.
* Renamed to ChargeConservingCIC to emphasize connection with CIC.
Added an XML file parser based on the Java SAX API.
Enabled parser in MainBatch.
Added handling of parameterless startup.
Changed error message for the SAXException.
Added main diagnostics class as well as an interface for diagnostic methods.
Split particle and grid diagnostic methods.
Diagnostic methods are now based on interfaces. (again)
Defined output interface for UI.
Implemented total kinetic energy diagnostic method.
* Added a method to gather the output form LocalDiagnostics.
* Added diagnostic methods list to the Settings class.
* Removed old stuff from MainBatch and added diagnostics.
Removed hardcoded energy diagnostics from diagnostics class.
Added classes that write diagnostic data to disk and incorporated them in MainBatch.
Renamed diagnostic method.
Renamed for consistency.
Added base classes for grid diagnostics output.
Corrected typos.