Merge pull request #76 from aipp/graphicspanel

Add second panel for graphical display of phase space
Merge pull request #77 from aipp/electricfield

Add new panel to display the electric field
Initial conditions are now largely independent off the chosen grid step, this was achieved by considering charge density instead of charge in the FFT routine by getting sure that each charge is treated like a uniformly charged rectangle of the size of an elementary cell. For this purpose measurement of snapshot files has been added, now we can do 3D plots of some grid quantities.
Merge with master, minor manual changes were needed.

Conflicts:
	pixi/src/main/java/org/openpixi/pixi/ui/Particle2DPanel.java
Merge pull request #78 from dgelfand/master

Initial conditions grid step independent.
Revert "Initial conditions grid step independent."
Merge pull request #80 from openpixi/revert-78-master

Revert "Initial conditions grid step independent."
Bug fix in the XML parser: set simulation properties correctly.

Set simulation width and height instead of timestep.
EmptyPoissonSolver added. New initial conditions for testing purposes added.
Merge pull request #79 from aipp/file

Load initial settings from a YAML file
Merge pull request #81 from aipp/bugfix

Bug fix in the XML parser: set simulation properties correctly.
Revert "Revert "Initial conditions grid step independent."" Now the Empty PoissonSolver is included, so the new version should compile without problems.

This reverts commit 0a1cb7742cd1be2ecd04973b26d2cdc96494d393.
Merge changes made by Andreas together with a reverted revert into my master branch.
Merge pull request #83 from dgelfand/master

A running version with all changes by Andreas and Daniil included.
Move code of file tab into separate class FileTab.
Add menu item to split panel horizontally or vertically.
Start from single panel in the main window and split it on demand.
Fix splitting of left component.
Close panel
Create common superclass AnimationPanel for graphics panels.