PIConGPU 0.3.0: Bremsstrahlung, EmZ, Thomas-Fermi, Improved Lasers, C++11

This is the first release of PIConGPU requiring C++11. We added a newly developed current solver (EmZ), support for the generation of Bremsstrahlung, Thomas-Fermi Ionization, Laguerre-modes in the Gaussian-Beam laser, in-simulation plane for laser initialization, new plugins for in situ visualization (ISAAC), a generalized particle calorimeter and a GPU resource monitor. Initial support for clang (host and device) has been added and our documentation has been streamlined to use Sphinx from now on. Please refer to our ChangeLog for a full list of features, fixes and user interface changes before getting started. We also started continuous documentation ("a manual") with Sphinx: https://picongpu.readthedocs.io This page will in the mid time frame replace our wiki and will allow you to select a specific version of PIConGPU. Such a "release-aware documentation" is important to us since our tools, workflows and models naturally change over time (for the better). Also, you can contribute to it via pull requests! Thanks to Axel Huebl, René Widera, Richard Pausch, Alexander Matthes, Alexander Grund, Marco Garten, Heiko Burau, Alexander Debus, Erik Zenker, Bifeng Lei and Klaus Steiniger for contributions to this release