fbpic/fbpic: 0.9.0 Better support for creation and continuous injection of particles

<p>This version improves several features related to creation and continuous injection of particles.</p> <p>New features:</p> <ul> <li>New species can now be created with the new method <code>add_new_species</code> of the <code>Simulation</code> object. (See <a href="https://github.com/fbpic/fbpic/pull/228">228</a>) This is particularly useful for simulations involving ionization. (See <a href="https://github.com/fbpic/fbpic/pull/231">231</a>)</li> <li>Macroparticles with zero weight will not be created anymore. This saves time and memory when running simulations where the plasma <code>dens_func</code> is 0 over long distances (<a href="https://github.com/fbpic/fbpic/pull/223">223</a>). In addition, a warning is now printed if the <code>dens_func</code> returns negative values (<a href="https://github.com/fbpic/fbpic/pull/227">227</a>).</li> <li>Electron bunches can now be injected through a plane, in order to avoid space charge effects over long distances in the boosted frame (<a href="https://github.com/fbpic/fbpic/pull/186">186</a>).</li> <li>MPI communications involve less synchronization (<a href="https://github.com/fbpic/fbpic/pull/217">#217</a>) and include support for GPUDirect (<a href="https://github.com/fbpic/fbpic/pull/226">226</a>). Note that this is for testing purposes for the moment. Multi-GPU/multi-CPU are still not officially supported.</li> <li>The default number of guard cells and damp cells has been increased. (<a href="https://github.com/fbpic/fbpic/pull/229">229</a>)</li> </ul> <p>Miscellaneous:</p> <ul> <li>The style of warnings has been changed (<a href="https://github.com/fbpic/fbpic/pull/227">227</a>).</li> <li>This new release includes the cross-deposition scheme (<a href="https://github.com/fbpic/fbpic/pull/202">202</a>). This is for testing purposes for the moment.</li> <li>The arrays <code>z</code> and <code>r</code> of the interpolation grid are now calculated on the fly. (<a href="https://github.com/fbpic/fbpic/pull/215">215</a>)</li> </ul> <p>Bug fixes:</p> <ul> <li>The restart from checkpoint were slightly incorrect, due to an incorrect size of the grid, by one cell size (<a href="https://github.com/fbpic/fbpic/pull/224">224</a>). This is now fixed.</li> <li>Continuous injection (with moving window) used to be incorrect for particles with different number of particles per cell in z. This is now fixed. (<a href="https://github.com/fbpic/fbpic/pull/230">230</a>)</li> <li>Injection of a Gaussian bunch in the boosted frame did not involve checking that the particles are in the correct local subdomain. This is now fixed. (<a href="https://github.com/fbpic/fbpic/pull/232">232</a>)</li> </ul&gt