Update readme and wrote separate readme's for packages

README.md

-pystencils
-==========
+lbmpy
+=====
 
+Run fast fluid simulations based on the lattice Boltzmann method in Python.
 
-![alt text](doc/img/logo.png)
+![alt text](doc/img/logo.png)
\ No newline at end of file
+
+
+Installation
+------------
+
+```bash
+export PIP_EXTRA_INDEX_URL=https://www.walberla.net/pip
+pip install lbmpy[interactive]
+```
+
+
+Without `[interactive]` you get a minimal version with very little dependencies.
+
+All options:
+-  `gpu`: use this if nVidia GPU is available and CUDA is installed
+- `alltrafos`: pulls in additional dependencies for loop simplification e.g. libisl
+- `interactive`: installs dependencies to work in Jupyter including image I/O, plotting etc.
+
+Options can be combined e.g.
+```bash
+pip install pystencils[interactive,gpu,doc]
+```
+
+
+Documentation
+-------------
+
+Read the docs [here](http://software.pages.walberla.net/pystencils/lbmpy)